GPCRs as Therapeutic Targets, 2 Volume Set E-Book
303,99 €
Mehr erfahren.
- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
A thorough discussion of the structure, pharmacology, function, and role of G protein-coupled receptors In GPCRs as Therapeutic Agents, distinguished researcher Dr. Annette Gilchrist delivers an authoritative and in-depth compendium of a vibrant and active area of academic and industrial drug discovery. The book serves as an important reference for new and experienced researchers studying G protein-coupled receptors and discusses the molecular pharmacology of this important target class. It also includes up-to-date material on GPCR structures and structure-based drug design. The book explores the role of GPCRs in the treatment of disease and novel approaches to their study. In addition to providing information on the structure, pharmacology, and function of GPCRs, it discusses their role in disease states, and advances new methods for measuring GPCR activity in an accessible and engaging way. The book includes: * A thorough introduction to the molecular pharmacology of G protein-coupled receptors, including up-to-date material on GPCR structures and structure-based drug design * In-depth discussions of the evolving pharmacology for GPCRs, intracellular trafficking, and subcellular GPCR signaling * Comprehensive explorations of allosteric modulation, receptor dimerization, deorphanization, and ubiquitination * Fulsome treatments of the role played by GPCRs in the treatments of cancer, substance use disorders, cerebrovascular diseases, and metabolic diseases Perfect for researchers in biochemistry, cell biology, and pharmacology, GPCRs as Therapeutic Agents will also earn a place in the libraries of professionals working in medicinal chemistry, structural biology, and clinical pharmacology.
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 1886
Veröffentlichungsjahr: 2022
Ähnliche
Table of Contents
Cover
Volume 1
Title Page
Copyright
Preface
List of Contributors
Part I: GPCR Pharmacology/Signaling
1 An Overview of G Protein Coupled Receptors and Their Signaling Partners
1.1 Overview of GPCR Superfamily
1.2 GPCR Signaling
1.3 GPCR Pharmacology
1.4 Forging Ahead
References
2 Recent Advances in Orphan GPCRs Research and Therapeutic Potential
2.1 Introduction
2.2 Concise History of Orphan GPCRs Research
2.3 Current Deorphanization Strategies
2.4 Analysis of Orphan GPCR Function and Expression Profiles
2.5 Conclusion and Perspectives
Acknowledgments
References
3 The Evolution of Our Understanding of “GPCRs”
3.1 Introduction
3.2 The “Perfect Storm” of Ideas Enters Pharmacology
3.3 Biased Receptor Signaling
3.4 Continuing Influences
3.5 Conclusion
References
4 Approaching GPCR Dimers and Higher‐Order Oligomers Using Biophysical, Biochemical, and Proteomic Methods
4.1 Introduction
4.2 Biochemical or Antibody‐Based Methods to Study GPCR Dimers and Higher‐Order Oligomers
4.3 Biophysical Approaches to Study GPCR Dimers and Higher‐Order Oligomers
4.4 Engineering Ligands as Tools to Study GPCR Dimers
4.5 Proteomic Approaches to Study GPCR Dimers and Higher‐Order Oligomers
4.6 Perspectives
References
5 Arrestin and G Protein Interactions with GPCRs: A Structural Perspective
5.1 Overview of GPCR Biology
5.2 Structural Determinants of G Protein and Arrestin Coupling
5.3 Selectivity Between G Proteins
5.4 Arrestins‐Binding Differences
5.5 Modulating GPCR Signaling
5.6 Case Study: Dopamine Receptor Family
Funding
References
6 GPCRs at Endosomes: Sorting, Signaling, and Recycling
6.1 Recycling Pathways for GPCRs at Endosomes
6.2 Sequence‐Directed GPCR Recycling
6.3 Endosomes as a Platform for Sorting into Recycling Pathways: Structure and Function
6.4 Endosomal Recycling Complexes
6.5 GPCR Signaling from Endosomes
6.6 Conclusion
References
7 Posttranslational Control of GPCR Signaling
7.1 Introduction
7.2 Posttranslational Modifications
7.3 Cytosolic Peptide Motifs and Their Accessory Proteins
7.4 Summary
References
8 GPCR Signaling from Intracellular Membranes
8.1 Introduction
8.2 How Do GPCRs Get to a Given Location?
8.3 Activation of Intracellular GPCRs
8.4 Signaling of Intracellular GPCRs
8.5 Functional Roles of Intracellular GPCRs
8.6 GPCR Localization Plays an Important Role in Disease Processes
8.7 Looking Forward
Funding
Abbreviations
References
Part II: Structures and Structure‐Based Drug Design
9 Ten Years of GPCR Structures
9.1 Introduction
9.2 Origins of GPCR Structure
9.3 Early Platform Development to Expand Beyond Rhodopsin
9.4 The First Wave of GPCR Structural Biology
9.5 The Impact of the GPCR Consortium: Widening Access to Ligands
9.6 A Unified Analysis Across GPCR Families
9.7 The Next 10 Years of Discovery
References
10 Activation of Class B GPCR by Peptide Ligands: General Structural Aspects
10.1 Structure Determination of Class B GPCRs
10.2 The Receptor‐Bound Class B Peptides
10.3 The NTD and Hinge Region
10.4 The Activated Class B TMD
10.5 Ligand Interactions with the Extracellular Loops
10.6 Interactions Between Class B GPCRs and G
s
Protein
10.7 Conclusion
References
11 Dynamical Basis of GPCR–G Protein Coupling Selectivity and Promiscuity
11.1 Introduction and Scope
11.2 Delineating G Protein Selectivity Determinants by Combining Sequence Analysis with Structural Information
11.3 Dynamical Basis of GPCR Signaling
11.4 Cellular Resonance Energy Transfer Studies Reveal a Spectrum of G Protein Activities
11.5 Spectroscopic Approaches to Probe the Dynamics of GPCR–G Protein Complexes
11.6 Molecular Dynamics Simulations Reveal Allosteric Communication from Ligand to Effector Binding Interface
11.7 An Integrated Approach Using MD and Experiment Measurements
11.8 Towards Addressing GPCR–G Protein Coupling Promiscuity
11.9 Towards the Structural Basis of Agonist Efficacy and Allosteric Modulation of GPCR Signaling
Acknowledgments
References
12 Virtual Screening and Bioactivity Modeling for G Protein‐Coupled Receptors
12.1 Introduction
12.2 Overview of Virtual Screening
12.3 Conventional Virtual Screening
12.4 Chemogenomics‐Based Virtual Screening
12.5 Bioactivity Modeling with Machine Learning
12.6 Inverse Virtual Screening
12.7 Conclusion
Acknowledgments
References
13 Importance of Structure and Dynamics in the Rational Drug Design of G Protein‐Coupled Receptor (GPCR) Modulators
13.1 Introduction
13.2 Structure Determination of GPCR
13.3 Importance of Dynamics in Characterizing GPCR Structure and Function for the Design of New GPCR Compounds
13.4 Strategies for the Design of New GPCR Modulators
13.5 Concluding Remarks
Acknowledgment
References
14 Signaling, Physiology, and Targeting of GPCR‐Regulated Phospholipase C Enzymes
14.1 Background
14.2 Regulation of PLCβ and PLCε by G Proteins and GPCRs
14.3 Diseases and Phenotypes Associated with PLCβ and PLCε
14.4 Opportunities to Therapeutically Target GPCR–G Protein–PLC Signaling
14.5 Conclusion and Perspectives
References
Note
Volume 2
Title Page
Copyright
Preface
List of Contributors
Part III: GPCRs and Disease
15 G Protein‐Coupled Receptors in Metabolic Disease
15.1 Introduction
15.2 Metabolic Disease
15.3 G Protein‐Coupled Receptors
15.4 Discussion by Organ
15.5 Summary
Acknowledgments
References
16 Endothelin Receptors in Cerebrovascular Diseases
16.1 Introduction of Endothelin and Its Receptors
16.2 Pathophysiological Role of ET Receptors in Cerebrovascular Diseases: Distribution and Their Importance in Development of the CNS
16.3 Role of ET‐Receptor Agonists and Antagonists in the Management of Cerebrovascular Diseases
16.4 Clinical Development of Sovateltide, ET
B
Receptor Agonist, as a Drug for Cerebral Ischemia
16.5 Conclusions and Perspectives
References
17 The Calcium‐Sensing Receptor (CaSR) in Disease
17.1 Biochemical Features of the CaSR
17.2 CaSR Structure
17.3 CaSR (Patho)physiology
17.4 Therapeutic Effects of Drugs Targeting the CaSR
17.5 Concluding Remarks
References
Note
18 G Protein‐Coupled Receptors and Their Mutations in Cancer – A Focus on Adenosine Receptors
18.1 Introduction
18.2 GPCRs and Cancer
18.3 GPCR Mutations in Cancer
18.4 Adenosine Receptors and Cancer
18.5 Conclusion
References
19 Dopamine Receptors: Neurotherapeutic Targets for Substance Use Disorders
19.1 Introduction
19.2 Substance Use Disorders: A Crisis of Unmet Clinical Need
19.3 The Dopamine Hypothesis of Addiction
19.4 Overview of Dopaminergic Brain Pathways
19.5 Dopamine Neurotransmission
19.6 Alterations of Dopamine Signaling by Drugs of Abuse
19.7 Dopamine Receptors and Their Signaling
19.8 Dopamine D1 Receptors
19.9 Dopamine D5 Receptors
19.10 Dopamine D2 Receptors
19.11 Dopamine D3 Receptors
19.12 Dopamine D4 Receptors
19.13 Dopamine Receptors in Substance Use Disorders and Drug Taking: Preclinical Models
19.14 Dopamine Receptor Pharmacology for Substance Use Disorders
19.15 Dopamine D1 Receptor Subfamily Ligands
19.16 Dopamine D2 Receptor Subfamily Ligands
Abbreviations
Acknowledgments
References
20 PTHR1 in Bone
20.1 Introduction
20.2 PTHRs
20.3 PTHR1 Ligands
20.4 Biochemical Reactions
20.5 Physiological Function of PTHR1 in Bone
20.6 PTHR1 as a Therapeutic Target in Osteoporosis
20.7 PTHR1: PTH as Treatment for Other Bone Diseases
20.8 PTHR1 in Cancer
20.9 Conclusions and Future directions
References
21 Activators of G‐Protein Signaling in the Normal and Diseased Kidney
21.1 Introduction
21.2 Heterotrimeric G‐Protein Subunits in the Kidney
21.3 Identification of AGS Proteins
21.4 Activators of G‐Protein Signaling in the Kidney
21.5 Summary and Perspective
References
Part IV: Novel Approaches
22 Screening and Characterizing of GPCR–Ligand Interactions with Mass Spectrometry‐Based Technologies
22.1 Introduction
22.2 High‐Throughput GPCR Ligand Screening with Affinity MS
22.3 Characterization of GPCR–Ligand Interactions with MS‐Based Techniques
22.4 Conclusion
Acknowledgments
Conflict of Interest
References
23 Bioluminescence Resonance Energy Transfer (BRET) Technologies to Study GPCRs
23.1 Introduction
23.2 BRET Overview: Advantages and Limitations
23.3 Emerging BRET Techniques
23.4 Novel NanoBRET Assays
23.5 Genome‐Editing and Bioluminescent Techniques
23.6 Summary
References
24 The Application of
19
F NMR to Studies of Protein Function and Drug Screening
24.1 Introduction
24.2 Fluorinated Amino Acid Analogs Used in Biosynthetic Labeling Approaches
24.3 An Overview of Chemical Tagging and Orthogonal Labeling
24.4 Orthogonal Methods for Protein Labeling with
19
F NMR Probes
24.5 Current Studies of Conformational Dynamics of Proteins
24.6 Enhancing
19
F NMR Spectroscopy with Topology and Distance Measurements
24.7 Studies of Ligand Interactions and Drug Discovery by
19
F NMR
24.8 Final Comments
Acknowledgments
References
25 Optical Approaches for Dissecting GPCR Signaling
25.1 Introduction
25.2 Optical Control of GPCRs
25.3 Optical Control of Signaling Downstream of GPCRs
25.4 Experimental Applications and Biological Insights
25.5 Future Directions
25.6 Concluding Remarks
References
26 GPCR Signaling in Nanodomains: Lessons from Single‐Molecule Microscopy
26.1 Introduction
26.2 The Basic Mechanisms of GPCR Signaling
26.3 The Structural Basis for GPCR Signaling
26.4 Emerging Concepts in GPCR Signaling
26.5 Single‐Molecule Microscopy
26.6 Applications of Single‐Particle Tracking
26.7 Single‐Molecule Localization Super‐Resolution Microscopy Methods
26.8 Single‐Molecule FRET
26.9 Fluorescence Correlation Spectroscopy
26.10 Single‐Molecule Microscopy Versus Ensemble Methods
26.11 Early Single‐Molecule Studies
26.12 Lessons from Single‐molecule Microscopy
In Vitro
26.13 Lessons from Single‐molecule Microscopy in Living Cells
26.14 Hot Spots for Receptor‐G protein Interactions
26.15 Summary and Future Perspectives
References
Index
End User License Agreement
List of Tables
Chapter 2
Table 2.1 Endogenous expression of orphan and understudied GPCRs in cancer....
Table 2.2 Phenotype of orphan and understudied GPCRs gene deleted mice.
Chapter 5
Table 5.1 Representatives for allosteric modulators of G protein‐coupled rec...
Chapter 8
Table 8.1 Current list of intracellular GPCRs with strong evidence for locat...
Table 8.2 Primary subcellulardestinations of GPCRs.
Chapter 9
Table 9.1 GPCR structures determined before formation of the GPCR consortium...
Table 9.2 GPCR structures determined by GPCR consortium labs.
Table 9.3 Class specific alignment indices.
Chapter 10
Table 10.1 List of structures of class B GPCRs that include the TMD, updated...
Chapter 13
Table 13.1 Brief descriptions of several structure prediction tools that cat...
Table 13.2 Brief descriptions of several sequence alignment programs.
Chapter 14
Table 14.1 Summary of physiological roles of PLCε in cancer.
Chapter 16
Table 16.1 This table summarizes the active and completed clinical trials fo...
Table 16.2 Summary of clinical trial study design and results of sovateltide...
Chapter 18
Table 18.1 Examples of anti‐cancer drugs and antibodies currently under clin...
Chapter 21
Table 21.1 List of AGS proteins and alternate names.
Chapter 22
Table 22.1 A variety of technologies applied to screening or characterizing ...
Chapter 25
Table 25.1 Opsin GPCRs used as optogenetic tools.
Table 25.2 List of tools for optical control of intracellular signaling.
List of Illustrations
Chapter 2
Figure 2.1 Recently developed assays to monitor GPCRs activation. (a) PREST‐...
Figure 2.2 Light‐sensitive chimeric GPCRs. (a) Light activation of rhodopsin...
Chapter 3
Figure 3.1 Linkage models for receptor systems. (a) Extended ternary complex...
Figure 3.2 Energy landscape with some identified energy states associated wi...
Figure 3.3 Two methods of depicting biased signaling in multiple ligands for...
Chapter 4
Figure 4.1 Biochemical approaches to studying GPCR dimers. (a) Co‐immunoprec...
Figure 4.2 Resonance energy transfer‐based approaches to studying GPCR dimer...
Figure 4.3 Proteomic approaches to studying GPCR dimers. Enzymes such as APE...
Chapter 5
Figure 5.1 Schematic diagram of GPCR signaling pathways highlighting the shi...
Figure 5.2 Structural features of the adenosine A
2A
receptor in the inactive...
Figure 5.3 Electrostatic potential surfaces of the different partners bound ...
Chapter 7
Figure 7.1 A diagram of GPCR posttranslational modifications. N‐Linked glyco...
Figure 7.2 A model of GPCR phosphorylation. GPCRs are phosphorylated on intr...
Figure 7.3 Ubiquitination regulates GPCR signaling and endocytic trafficking...
Figure 7.4 The cytosolic peptide motifs of protease‐activated receptor 1. PA...
Chapter 8
Figure 8.1 Overview of pathways used by various GPCRs to reach intracellular...
Figure 8.2 Proposed diffusion–retention model targeting GPCRs to the inner n...
Figure 8.3 Schematic representations of the nuclear reticulum. Left upper pa...
Figure 8.4 Ligand activation of intracellular GPCRs. Several different strat...
Chapter 9
Figure 9.1 Timeline representing important events in the evolution of GPCR s...
Figure 9.2 Schematic of the methodology utilized for overlaying structures a...
Figure 9.3 Structure gallery of key GPCR structures determined since bovine ...
Chapter 10
Figure 10.1 Structural elements of class B GPCRs and their ligands. (a) Sche...
Figure 10.2 Ligand binding at class B GPCRs. (a) Ribbon representation of th...
Figure 10.3 Stalk and extracellular loops of inactive and active class B rec...
Figure 10.4 Ligand‐induced TMD conformational changes at class B GPCRs. (a) ...
Figure 10.5 Biased agonism at the GLP‐1R. Superimposition of GLP‐1R bound to...
Figure 10.6 High structural homology of G
s
proteins in complex with class B ...
Chapter 11
Figure 11.1 (a) Trajectory connecting GPCR and G protein sequence to GPCR fu...
Figure 11.2 GPCR‐G protein complex structures show a range of conformational...
Chapter 12
Figure 12.1 Hypothetical 10‐bit fingerprints for Oliceridine. (a) A path‐bas...
Figure 12.2 Representative portion of PDB file. The portions with the “Recor...
Figure 12.3 Typical machine learning workflow.
Figure 12.4 Classes of feature selection algorithms.
Figure 12.5 Schematic of SED. The approach is composed of three stages: long...
Chapter 13
Figure 13.1 Summary of recent topics in computational approaches and ligand ...
Figure 13.2 Schematic representation of the different allosteric binding sit...
Chapter 14
Figure 14.1 Domain structures of PLC subtypes. All PLC subtypes have 4 EF ha...
Figure 14.2 Structure of PLCβ. (a) Compact globular packaging of PH, EF‐hand...
Figure 14.3 Schematic diagram of signaling pathways downstream of four GPCR ...
Figure 14.4 Subcellular localization of PLCβ and PLCε. Subcellular compartme...
Chapter 16
Figure 16.1 Diagram illustrating synthesis of ET peptide and interaction wit...
Figure 16.2 Schematic diagram illustrating the main contributory factors inv...
Figure 16.3 Overview of the effect of ET
B
receptor agonist sovateltide on ne...
Chapter 17
Figure 17.1 Endogenous CaSR agonists and allosteric modulators.
Figure 17.2 Synthetic CaSR allosteric modulators.
Figure 17.3 Structural features of the CaSR. (a) The CaSR is an obligate hom...
Figure 17.4 Extracellular calcium (Ca
2+
o
) is tightly regulated. Reduced ...
Chapter 18
Figure 18.1 GPCR signaling from extracellular to intracellular. Upon recepto...
Figure 18.2 GPCRs and their roles in cancer hallmarks, adapted from Nieto Gu...
Figure 18.3 Effects of GPCR mutations on receptor pharmacology, such as (A) ...
Figure 18.4 Pro‐ and anti‐tumoral effects of adenosine receptors, A
1
AR, A
2A
A...
Chapter 19
Figure 19.1 Major dopaminergic (DA) brain pathways. The nigrostriatal dopami...
Figure 19.2 Dopamine receptor signaling pathways. (a) Dopamine D1‐like recep...
Figure 19.3 Structures of nonselective dopamine receptor agonists. The aster...
Figure 19.4 Structures of selective dopamine D1‐like receptor family ligands...
Figure 19.5 Structures of selective dopamine D2‐like receptor family ligands...
Chapter 21
Figure 21.1 Proposed mechanisms of action by the different groups of AGS pro...
Figure 21.2 Protein structure of AGS proteins. AGS proteins are listed in th...
Figure 21.3 Localization of AGS proteins in different segments of the kidney...
Chapter 22
Figure 22.1 Outline of accelerated affinity MS with iterative selection. (a)...
Figure 22.2 Outline of Membrane‐based affinity MS. (a) Experimental workflow...
Figure 22.3 Ligand binding characterization by ALIS‐based assays: (a)
K
d
of ...
Figure 22.4 Native MS for intact GPCR complex analysis: (a) Illustration of ...
Chapter 23
Figure 23.1 Schematic diagram of BRET between C′‐terminally luciferase‐tagge...
Figure 23.2 A simplified schematic representation of subcellular marker loca...
Figure 23.3 NanoBRET ligand binding at over‐expressed Nluc/A
2B
receptors. Li...
Figure 23.4 Examples of using NanoBiT for BRET assays. (a) Using SmBiT‐LgBiT...
Figure 23.5 Design and validation of gene‐edited adenosine A
2B
receptors. (a...
Chapter 24
Figure 24.1 The free energy landscape. GPCRs are envisioned to sample a dive...
Figure 24.2 (a) Current thiol‐specific
19
F NMR tags include BTFA, BTFMA, and...
Figure 24.3 Orthogonal labeling methods achieve site‐selective labeling by r...
Figure 24.4 Overlay of 1D NMR spectra comparing a zymogen precursor prethrom...
Figure 24.5 (a) Structures of
L
‐Asp bound protomer in the outward facing and...
Figure 24.6 The FAXS experiment performed in direct (left) and competition (...
Chapter 25
Figure 25.1 Opsin GPCR photocycles. Bleaching pigments release all‐trans ret...
Figure 25.2 Control of G protein or arrestin signaling. (a) G protein biased...
Figure 25.3 Subcellular optogenetics. Subcellular control of cell signaling ...
Chapter 26
Figure 26.1 Conformational changes during the formation of an active recepto...
Figure 26.2 Studying membrane proteins by single‐molecule microscopy. (a) Th...
Figure 26.3 Schematic representation of GPCR signaling hot spots at the plas...
Guide
Cover Page
Title Page
Copyright
Preface
List of Contributors
Table of Contents
Begin Reading
Index
Wiley End User License Agreement
Pages
iii
iv
xvii
xviii
xix
xx
xxi
xxii
xxiii
xxiv
xxv
xxvi
xxvii
xxviii
xxix
xxx
1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
iii
iv
xv
xvi
xvii
xviii
xix
xx
xxi
xxii
xxiii
xxiv
xxv
xxvi
xxvii
xxviii
521
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
805
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
979
980
981
982
983
984
985
986
987
988
989
GPCRs as Therapeutic Targets
Volume 1
Edited by
Annette Gilchrist
College of Pharmacy-Downers Grove, Midwestern University, Downers Grove, IL, USA
This edition first published 2023
© 2023 by John Wiley & Sons, Inc.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.
The right of Annette Gilchrist to be identified as the author of the editorial material in this work has been asserted in accordance with law.
Registered Office
John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA
Editorial Office
John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA
For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com.
Wiley also publishes its books in a variety of electronic formats and by print‐on‐demand. Some content that appears in standard print versions of this book may not be available in other formats.
Limit of Liability/Disclaimer of Warranty
In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of experimental reagents, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each chemical, piece of equipment, reagent, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.
Library of Congress Cataloging‐in‐Publication Data
Names: Gilchrist, Annette, editor.
Title: GPCRs as therapeutic targets / edited by Annette Gilchrist.
Other titles: G-protein-coupled receptors as therapeutic targets
Description: Hoboken, NJ : Wiley, 2023. | Includes bibliographical references and index.
Identifiers: LCCN 2022016266 (print) | LCCN 2022016267 (ebook) | ISBN 9781119564744 (cloth) | ISBN 9781119564799 (adobe pdf) | ISBN 9781119564720 (epub)
Subjects: MESH: Receptors, G-Protein-Coupled | Drug Delivery Systems
Classification: LCC RS199.5 (print) | LCC RS199.5 (ebook) | NLM QU 55.7 | DDC 615/.6–dc23/eng/20220608
LC record available at https://lccn.loc.gov/2022016266
LC ebook record available at https://lccn.loc.gov/2022016267
Cover image: © Jon Burkhart; acrylic (Media)
Cover design by Wiley
Preface
G protein‐coupled receptors (GPCRs) are the largest group of cell surface receptors. They regulate nearly all known human physiological processes from the sensory modalities of vision, taste, and smell to hormones that control our growth and development to neurotransmitters that govern behavior. Given their role in normal homeostasis and a broad array of pathological conditions including cancer, diabetes, cardiovascular disease, and asthma to name just a few, they serve as the targets for hundreds of drugs and more recently biologics such as monoclonal antibodies. Yet our understanding of GPCRs continues to evolve and texts that discuss these receptors must constantly be revisited. For example, we are just beginning to appreciate the importance of genetic variation in targeted GPCRs.
In the 30 years I have studied GPCRs many novel pharmacological concepts have been advanced. We have seen the emergence of constitutively active GPCRs and inverse agonism, arrestin signaling and functional selectivity, receptor dimerization, and signaling through subcellular receptors. We have seen many GPCRs without known endogenous ligands (orphans) undergo deorphanization, and accepted that some orphan receptors may only function constitutively in a ligand‐independent manner. Advances in our understanding of their basal activity, their ability to bind a diverse array of ligands, how they communicate a signal across the cell membrane or within the cells, when they dimerize, their crosstalk with other receptors, and that their genetic variation can lead to disease or differences in drug response has expanded our appreciation for GPCRs. In addition, the depth of our understanding of GPCR pharmacology has in turn altered the drug discovery process itself, expanding the ways in which they are screened for compounds that modulate their signaling.
This two volume book set is organized into 26 chapters and will serve as a resource for any scientists investigating GPCRs, be it in academia or industry. The first volume provides in‐depth information about the molecular pharmacology of this important target class and presents up‐to‐date material on GPCR structures and structure based drug design. There are eight chapters on the evolving pharmacology for GPCRs, including chapters discussing allosteric modulation, receptor dimerization, deorphanization, ubiquitination, intracellular trafficking, and subcellular GPCR signaling. The next six chapters discuss the rapidly growing field of GPCR structures and structure based drug design. Included in this section are chapters on the structural basis of G protein selectivity, as well as rational drug design for not only GPCRs but downstream signaling molecules such as phospholipase C. The second volume includes information on the role of GPCRs in disease and novel approaches for studying this receptor family. There are seven chapters addressing how GPCRs play a role in a wide range of pathological states including cancer, substance use disorders, cerebrovascular disease, and metabolic disease. The final five chapters present recent approaches employed to study GPCRs including mass spectrometry, bioluminescence, single molecule microscopy, and optogenetics. Together, the two volume book set provides a thorough overview of GPCRs in terms of their structure, pharmacology, function, and role in disease states, and provides information on novel approaches to measure GPCR activity.
Annette GilchristMidwestern University
List of Contributors
John A. Allen
Department of Pharmacology and Toxicology
University of Texas Medical Branch
Galveston, TX
USA
and
Department of Neuroscience and Cell Biology
University of Texas Medical Branch
Galveston, TX
USA
and
Center for Addiction Research
University of Texas Medical Branch
Galveston, TX
USA
Salete J. Baptista
Data‐Driven Molecular Design Group
CNC – Center for Neuroscience and Cell Biology
University of Coimbra
Coimbra
Portugal
and
Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico
Universidade de Lisboa
Bobadela LRS
Portugal
Carlos A.V. Barreto
Data‐Driven Molecular Design Group
CNC – Center for Neuroscience and Cell Biology
University of Coimbra
Coimbra
Portugal
and
Institute for Interdisciplinary Research, University of Coimbra
PhD Programme in Experimental Biology and Biomedicine
Coimbra
Portugal
Eric Bell
Department of Computational Medicine and Bioinformatics
University of Michigan
Ann Arbor, MI
USA
Kyla Bourque
Department of Pharmacology and Therapeutics
McGill University
Montréal, Québec
Canada
Mariaelana Brenner
Department of Medicine, Division of Endocrinology, Diabetes and Metabolism
University of Illinois College of Medicine
Chicago, IL
USA
Seema Briyal
Pharmaceutical Sciences
Midwestern University
Downers Grove, IL
USA
Michael R. Bruchas
Center of Excellence in the Neurobiology of Addiction, Pain, and Emotion, Department of Anesthesiology
University of Washington
Seattle, WA
USA
and
Department of Pharmacology
University of Washington
Seattle, WA
USA
Beatriz Bueschbell
Department of Pharmaceutical and Medicinal Chemistry
Pharmaceutical Institute, University of Bonn
Bonn
Germany
Davide Calebiro
College of Medical and Dental Sciences
Institute of Metabolism and Systems Research, University of Birmingham
Birmingham
UK
and
Centre of Membrane Proteins and Receptors (COMPARE)
Universities of Nottingham and Birmingham
UK
Wallace Chan
Department of Computational Medicine and Bioinformatics
University of Michigan
Ann Arbor, MI
USA
and
Department of Biological Chemistry
University of Michigan
Ann Arbor, MI
USA
and
Department of Pharmacology
University of Michigan
Ann Arbor, MI
USA
Naincy R. Chandan
Department of Pharmacology
University of Michigan Medical School
Ann Arbor, MI
USA
Sun Choi
College of Pharmacy and Graduate School of Pharmaceutical Sciences
Ewha Womans University
Seoul
Republic of Korea
Irene Coin
Faculty of Life Sciences
Institute of Biochemistry, Leipzig University
Leipzig
Germany
Bryan A. Copits
Pain Center, Department of Anesthesiology
Washington University School of Medicine
St. Louis, MO
USA
Natasha C. Dale
Molecular Endocrinology and Pharmacology
Harry Perkins Institute of Medical Research, QEII Medical Centre
Nedlands, Western Australia
Australia
and
Centre for Medical Research
The University of Western Australia
Crawley, Western Australia
Australia
and
National Centre
Australian Research Council Centre for Personalised Therapeutics Technologies
Australia
Michael R. Dores
Department of Biology
Hofstra University
Hempstead, NY
USA
Stefan Ernicke
Faculty of Life Sciences, Institute of Biochemistry
Leipzig University
Leipzig
Germany
Daniel E. Felsing
Department of Pharmacology and Toxicology
University of Texas Medical Branch
Galveston, TX
USA
and
Center for Addiction Research
University of Texas Medical Branch
Galveston, TX
USA
Geordi Frere
Department of Chemistry, Chemical and Physical Sciences
University of Toronto
Mississauga, ON
Canada
Elyssa Frohlich
Department of Pharmacology and Therapeutics
McGill University
Montréal, Québec
Canada
Annette Gilchrist
Department of Pharmaceutical Sciences, College of Pharmacy‐Downers Grove
Midwestern University
Downers Grove, IL
USA
Sophie Gough
Department of Medicine, Division of Endocrinology, Diabetes and Metabolism
University of Illinois College of Medicine
Chicago, IL
USA
Jerome Gould
Department of Chemistry, Chemical and Physical Sciences
University of Toronto
Mississauga, ON
Canada
Karen J. Gregory
Drug Discovery Biology
Monash Institute of Pharmaceutical Science, Monash University
Parkville
Australia
Jak Grimes
College of Medical and Dental Sciences
Institute of Metabolism and Systems Research, University of Birmingham
Birmingham
UK
and
Centre of Membrane Proteins and Receptors (COMPARE)
Universities of Nottingham and Birmingham
UK
Anil Gulati
Pharmaceutical Sciences
Midwestern University
Downers Grove, IL
USA
and
Pharmazz, Inc.
Willowbrook, IL
USA
Patrick T. Gunning
Department of Chemistry, Chemical and Physical Sciences
University of Toronto
Mississauga, ON
Canada
Michael A. Hanson
SB SciTech
San Marcos, CA
USA
Steven K. Harmon
Department of Neuroscience
Washington University School of Medicine
Saint Louis, MO
USA
Advait Hasabnis
Department of Chemistry, Chemical and Physical Sciences
University of Toronto
Mississauga, ON
Canada
Terence E. Hébert
Department of Pharmacology and Therapeutics
McGill University
Montréal, Québec
Canada
Laura H. Heitman
Division of Drug Discovery and Safety
LACDR
Leiden University
The Netherlands
and
Oncode Institute
Leiden
The Netherlands
Carole Le Henaff
Department of Molecular Pathobiology
New York University College of Dentistry
New York, NY
USA
Iara C. Ibay
Department of Pharmaceutical Sciences, College of Pharmacy‐Downers Grove
Midwestern University
Downers Grove, IL
USA
Adriaan P. IJzerman
Division of Drug Discovery and Safety, LACDR
Leiden University
The Netherlands
Roshanak Irannejad
Department of Biochemistry and Biophysics
Cardiovascular Research Institute University of California
San Francisco, CA
USA
Ralf Jockers
Institut Cochin, CNRS, INSERM
Université de Paris
Paris
France
Elizabeth K.M. Johnstone
Molecular Endocrinology and Pharmacology
Harry Perkins Institute of Medical Research, QEII Medical Centre
Nedlands, Western Australia
Australia
and
Centre for Medical Research
The University of Western Australia
Crawley, Western Australia
Australia
and
National Centre
Australian Research Council Centre for Personalised Therapeutics Technologies
Australia
Yuh‐Jiin I. Jong
Department of Neuroscience
Washington University School of Medicine
Saint Louis, MO
USA
Tracy M. Josephs
Drug Discovery Biology
Monash Institute of Pharmaceutical Science, Monash University
Parkville
Australia
Andrew N. Keller
Drug Discovery Biology
Monash Institute of Pharmaceutical Science, Monash University
Parkville
Australia
Terry Kenakin
Department of Pharmacology
University of North Carolina School of Medicine
Chapel Hill, NC
USA
Brian T. Layden
Department of Medicine, Division of Endocrinology, Diabetes and Metabolism
University of Illinois College of Medicine
Chicago, IL
USA
and
Jesse Brown Veterans Affairs Medical Center
Department of Medicine, Section of Endocrinology
Chicago, IL
USA
Raudah Lazim
College of Pharmacy and Graduate School of Pharmaceutical Sciences
Ewha Womans University
Seoul
Republic of Korea
Kristen R. Lednovich
Department of Medicine, Division of Endocrinology, Diabetes and Metabolism
University of Illinois College of Medicine
Chicago, IL
USA
Yoonji Lee
College of Pharmacy
Chung‐Ang University
Seoul
Republic of Korea
Katie Leach
Drug Discovery Biology
Monash Institute of Pharmaceutical Science, Monash University
Parkville
Australia
Agostinho Lemos
Data‐Driven Molecular Design Group
CNC – Center for Neuroscience and Cell Biology
University of Coimbra
Coimbra
Portugal
Braden T. Lobingier
Department of Chemical Physiology and Biochemistry
Oregon Health and Sciences University
Portland, OR
USA
Yan Lu
iHuman Institute, ShanghaiTech University
Shanghai
China
and
School of Life Science and Technology
ShanghaiTech University
Shanghai
China
Miguel Machuqueiro
Departmento de Química e Bioquímica, Faculdade de Ciências
Universidade de Lisboa
BioISI‐Biosystems and Integrative Sciences Institute
Lisboa
Portugal
Pedro R. Magalhães
Departmento de Química e Bioquímica, Faculdade de Ciências
Universidade de Lisboa
BioISI‐Biosystems and Integrative Sciences Institute
Lisboa
Portugal
Rita Melo
Data‐Driven Molecular Design Group
CNC – Center for Neuroscience and Cell Biology
University of Coimbra
Coimbra
Portugal
and
Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico
Universidade de Lisboa
Bobadela LRS
Portugal
Ravi Mistry
College of Medical and Dental Sciences
Institute of Metabolism and Systems Research, University of Birmingham
Birmingham
UK
and
Centre of Membrane Proteins and Receptors (COMPARE)
Universities of Nottingham and Birmingham
UK
Irina S. Moreira
Data‐Driven Molecular Design Group
CNC – Center for Neuroscience and Cell Biology
University of Coimbra
Coimbra
Portugal
and
Department of Life Sciences, Faculty of Science and Technology
University of Coimbra
Coimbra
Portugal
and
CIBB – Center for Innovative Biomedicine and Biotechnology
University of Coimbra
Coimbra
Portugal
Pratanphorn Nakliang
College of Pharmacy and Graduate School of Pharmaceutical Sciences
Ewha Womans University
Seoul
Republic of Korea
Ashley N. Nilson
Department of Neuroscience and Cell Biology
University of Texas Medical Branch
Galveston, TX
USA
and
Center for Addiction Research
University of Texas Medical Branch
Galveston, TX
USA
Atsuro Oishi
Institut Cochin, CNRS, INSERM
Université de Paris
Paris
France
and
Department of Anatomy
Kyorin University Faculty of Medicine
Tokyo
Japan
and
Cancer RNA Research Unit
National Cancer Center Research Institute
Tokyo
Japan
Karen L. O'Malley
Department of Neuroscience
Washington University School of Medicine
Saint Louis, MO
USA
Patrick R. O'Neill
Hatos Center for Neuropharmacology
Department of Psychiatry and Biobehavioral Sciences
University of California Los Angeles
Los Angeles, CA
USA
Maria C. Orencia
GPCR Consortium
San Marcos, CA
USA
Aditya Pandey
Department of Chemistry, Chemical and Physical Sciences
University of Toronto
Mississauga, ON
Canada
and
Department of Biochemistry
University of Toronto
Toronto, ON
Canada
Nicola C. Partridge
Department of Molecular Pathobiology
New York University College of Dentistry
New York, NY
USA
Frank Park
Department of Pharmaceutical Sciences
University of Tennessee Health Science Center
Memphis, TN
USA
Kevin D.G. Pfleger
Molecular Endocrinology and Pharmacology
Harry Perkins Institute of Medical Research
QEII Medical Centre
Nedlands, Western Australia
Australia
and
Centre for Medical Research
The University of Western Australia
Crawley, Western Australia
Australia
and
National Centre
Australian Research Council Centre for Personalised Therapeutics Technologies
Australia
and
Dimerix Limited
Nedlands, Western Australia
Australia
Hoa T.N. Phan
Department of Pharmacology
University of Michigan Medical School
Ann Arbor, MI
USA
António J. Preto
Data‐Driven Molecular Design Group
CNC – Center for Neuroscience and Cell Biology
University of Coimbra
Coimbra
Portugal
and
Institute for Interdisciplinary Research, University of Coimbra
PhD Programme in Experimental Biology and Biomedicine
Coimbra
Portugal
Robert S. Prosser
Department of Chemistry, Chemical and Physical Sciences
University of Toronto
Mississauga, ON
Canada
and
Department of Biochemistry
University of Toronto
Toronto, ON
Canada
Talha Qadri
Department of Medicine, Division of Endocrinology, Diabetes and Metabolism
University of Illinois College of Medicine
Chicago, IL
USA
Shanshan Qin
iHuman Institute, ShanghaiTech University
Shanghai
China
Amaresh Ranjan
Pharmaceutical Sciences
Midwestern University
Downers Grove, IL
USA
Nícia Rosário‐Ferreira
Data‐Driven Molecular Design Group
CNC – Center for Neuroscience and Cell Biology
University of Coimbra
Coimbra
Portugal
and
Chemistry Department, Faculty of Science and Technology, Coimbra Chemistry Center
University of Coimbra
Coimbra
Portugal
Fredrik Sadler
Biochemistry, Molecular Biology and Biophysics Graduate Program
University of Minnesota
Minneapolis, MN
USA
Anke C. Schiedel
Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute
University of Bonn
Bonn
Germany
Wenqing Shui
iHuman Institute
ShanghaiTech University
Shanghai
China
and
School of Life Science and Technology
ShanghaiTech University
Shanghai
China
Sivaraj Sivaramakrishnan
Biochemistry, Molecular Biology and Biophysics Graduate Program
University of Minnesota
Minneapolis, MN
USA
and
Department of Genetics
Cell Biology, and Development
University of Minnesota
Minneapolis, MN
USA
Alan V. Smrcka
Department of Pharmacology
University of Michigan Medical School
Ann Arbor, MI
USA
Emma Tripp
College of Medical and Dental Sciences
Institute of Metabolism and Systems Research, University of Birmingham
Birmingham
UK
and
Centre of Membrane Proteins and Receptors (COMPARE)
Universities of Nottingham and Birmingham
UK
Nagarajan Vaidehi
Department of Computational and Quantitative Medicine, City of Hope Cancer Center
Beckman Research Institute of the City of Hope
Duarte, CA
USA
Xuesong Wang
Division of Drug Discovery and Safety
LACDR
Leiden University
The Netherlands
Gerard J. P. van Westen
Division of Drug Discovery and Safety
ALCDR
Leiden University
The Netherlands
Carl W. White
Molecular Endocrinology and Pharmacology
Harry Perkins Institute of Medical Research, QEII Medical Centre
Nedlands, Western Australia
Australia
and
Centre for Medical Research
The University of Western Australia
Crawley, Western Australia
Australia
and
National Centre
Australian Research Council Centre for Personalised Therapeutics Technologies
Australia
Jiansheng Wu
Department of Computational Medicine and Bioinformatics
University of Michigan
Ann Arbor, MI
USA
and
School of Geographic and Biological Information
Nanjing University of Posts and Telecommunications
Nanjing
China
Yang Zhang
Department of Computational Medicine and Bioinformatics
University of Michigan
Ann Arbor, MI
USA
and
Department of Biological Chemistry
University of Michigan
Ann Arbor, MI
USA
Part IGPCR Pharmacology/Signaling
1An Overview of G Protein Coupled Receptors and Their Signaling Partners
Iara C. Ibay and Annette Gilchrist
Department of Pharmaceutical Sciences, College of Pharmacy‐Downers Grove, Midwestern University, Downers Grove, IL, USA
1.1 Overview of GPCR Superfamily
G protein coupled receptors (GPCRs) encompass a large and diverse protein superfamily with over 800 members identified in the human genome. Of these 390 are odorant receptors, 33 are taste receptors, 10 are visual receptors, and 5 are pheromone receptors with the remaining receptors having non‐sensory mechanistic properties. Of these, ∼120 remain “orphan” receptors whose endogenous agonist is unknown [1]. A recent publication reported that 134 GPCRs are targets for some 700 medications approved in the United States or European Union accounting for ∼35% of the current drugs on the market [2].
The structures of GPCRs have been widely studied. All GPCR members are comprised of seven transmembrane (TM) domains with an extracellular amino (N)‐terminus that is highly varied, three extracellular loops, three intracellular loops, and an intracellular carboxyl (C)‐terminus. Detailed crystal structures of GPCRs have been utilized to understand their molecular and mechanistic properties. The Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC‐IUPHAR) classification divides GCPRs into six classes (Classes A–F) depending on their amino acid sequence and functional similarities (designed fingerprints) of the seven hydrophobic domains [3–5]. Class A GPCRs, also known as the rhodopsin‐like family, include the vast majority of receptors accounting for nearly 85% of GPCRs. Like all GPCRs, Class A receptors have seven TM helices, but there is an eighth helix, formed by a palmitoylated cysteine in the C‐terminal tail. For members of this class the orthosteric binding site is deep in the transmembrane helices [6]. There are around 70 members of Class B GPCRs, and multiple members belong to the secretin receptor family. Many members have a large N‐terminal domain of around 120 residues stabilized by disulfide bonds that serves as the orthosteric ligand binding side and is often activated by peptides [7]. Structures have been determined for several Class B receptors including glucagon receptor [8, 9], glucagon like peptide 1 (GLP‐1) receptor [10, 11], and parathyroid hormone receptor‐1 (PTH1) [12]. The adhesion family of GPCRs is phylogenetically related to class B receptors. They differ by possessing large extracellular N‐termini that are proteolytically cleaved at a conserved site within a larger autoproteolysis‐inducing domain. Class C contains 22 members, including the eight metabotropic glutamate receptors, γ‐aminobutyric acid (GABAB) receptors, calcium sensing receptors, taste receptors, and retinoic acid‐inducible orphan GPCRs. In addition to having a characteristically large extracellular domain to which ligands bind, many of the receptors are obligatory dimers [13]. In 2014, the Ray Stevens group provided the structure for metabotropic glutamate receptor 1 (mGlu1) [14]. This was followed in 2021 by structural information for the calcium‐sensing receptor [15, 16]. Class D GPCRs are found exclusively in fungi where they regulate survival and reproduction. Within Class D, the fungal GPCRs are further categorized into 10 classes on the basis of sequence homology. Chris Tate and colleagues recently provided the first structure for a Class D GPCR, namely that of Ste2 coupled to a heterotrimeric G protein and bound to α‐factor [17]. Class E GPCRs constitute cyclic adenosine monophosphate (cAMP) receptors from a protozoan amoeba (Dictyostelium discoideum) that are involved in chemotaxis. While the biochemical aspects of these receptors are well characterized, less is known about their structure [18, 19]. Class F GPCRs include the frizzled or smoothened receptors that are fundamental for mediating hedgehog signaling and Wnt binding. The Class F GPCRs ligands vary in size from small molecules and peptides to large proteins [7]. In 2019, Xiaochun Li's group published the structure of Smoothened bound to 24(S),25‐epoxycholesterol and coupled to a heterotrimeric Gi protein [20]. As Class A, B, C, D, and F structures have been published, the only GPCR family without an atomic level structure is Class E GPCRs.
With the advancement of technologies such as X‐ray crystallography, cryogenic electron microscopy (cryo‐EM), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopy techniques such as double electron–electron resonance (DEER), and molecular dynamics (MD) simulation many high resolution GPCR structures have been determined experimentally allowing us to understand some of the differences between individual receptors. In recent years, computational biology methods have utilized homology modeling and machine learning with programs such as MODELLER, RoseTTAFold, AlphaFold, and GPCR Dock to expand our ability to accurately predict GPCR structures [21–23]. To date, high resolution structures have been published for 107 different GPCRs with over 120 GPCR‐G protein complexes [24]. Structures for GPCRs have been determined with the receptor in active, inactive, as well as intermediate states with arrestin or heterotrimeric G proteins present [25]. A common feature of GPCRs that have 3D structures for both an antagonist bound state and agonist bound ternary complex is the large differences in receptor conformation between these states [26]. Early studies with Class A GPCRs indicated there was movement in the TM6 domain when an extracellular signal is bound [27]. Rasmussen et al. showed that there were changes in the cytoplasm facing side of the receptor, which included TM5 and TM6 moving outwards and TM7 and TM3 moving inwards [28]. Similar movements in TM3, TM6, and TM7 were observed with adenosine A2A receptors when bound to an agonist [29]. The outward movement of TM6 and inward movement of TM7 described for class A receptors, were also observed with Class B GPCRs including calcitonin, and GLP‐1R, although there were differences in helix 8 [25]. The 3D structures from X‐ray crystallography and cryo‐EM have provided in‐depth information about the orthosteric and allosteric binding sites of GPCRs. They have also provided novel insights to receptor dimerization [30]. Structural advances have been complemented by studies using MD simulation [31], deep mutational scanning [32], genome sequencing [33], and signal protein profiling [34, 35].
1.2 GPCR Signaling
GPCRs share functional likenesses, serving as biosensors; however, they exhibit versatility in the mechanisms by which they communicate extracellular signals to the cells. To this end, binding of an endogenous ligand produces a conformational change in the receptor that allows the recruitment of other proteins such as heterotrimeric G‐proteins, β‐arrestins, and G‐protein coupled receptor kinases (GRK
