Sprang Mechanisms and Pathways of Heterotrimeric G Protein Signaling

1. Auflage 2007
ISBN: 978-0-08-055269-9
Verlag: Elsevier Science & Techn.
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, Band Volume 74, 290 Seiten, Web PDF

Reihe: Advances in Protein Chemistry

This volume in the Advances in Protein Chemistry series features cutting-edge articles on topics in protein chemistry. This volume includes chapters on the structural basis of effector regulation and signal termination in heterotrimeric G?Ñ?n?nproteins; How do receptors activate G proteins; Some mechanistic insights into GPCR activation from detergent solubilized ternary complexes on beads; Activation of G protein coupled receptors; Kinetic analysis of g-protein-coupled receptor signaling using fluorescence resonance energy transfer in living cells; Regulation of Rho Guanine Nucleotide Exchange Factors (RhoGEFs) by G proteins.

Autoren/Hrsg.

Sprang, Stephen

Inhaltsverzeichnis

1;Cover;1
2;Contents;4
3;Preface;6
4;Chapter 1: Structural Basis of Effector Regulation and Signal Termination in Heterotrimeric Galpha Proteins;10
4.1;I. Introduction and Scope;12
4.2;II. A Selective Survey of Galpha Protein Structure and Function;14
4.3;III. Mechanisms of Effector Recognition and Regulation by GalphabullGTP;18
4.3.1;A. A Common Galpha:Effector Interface;20
4.3.2;B. Functional Consequences of Galpha:Effector Binding;24
4.4;IV. Signal Termination: The Mechanism of GTP Hydrolysis and Conformational Deactivation;32
4.4.1;A. Structure of the Ground State for GTP Hydrolysis;34
4.4.2;B. Reaction Trajectory for GTP Hydrolysis;37
4.5;V. Signal Termination Through GAPs and Effector GAP Domains;47
4.5.1;A. Deactivation of Galphaq by PLCbeta;48
4.5.2;B. RGS GAPs;50
4.5.3;C. Synergy Between RGS and Effector Domains;55
4.5.4;D. Deactivation of Galpha 13 by the alphaGAP Element of p115RhoGEF;56
4.6;VI. Conclusions;60
4.7;Acknowledgments;61
4.8;References;61
5;Chapter 2: How do Receptors Activate G Proteins?;76
5.1;I. Introduction;76
5.1.1;A. Structure of Heptahelical Receptors;77
5.1.2;B. Heterotrimeric G Protein Structure;79
5.2;II. Toward a Model of the Receptor-G Protein Complex;81
5.2.1;A. Structural Determinants of Receptor-G Protein Specificity;81
5.2.2;B. Point to Point Interactions Between Receptors and G Proteins;86
5.2.3;C. Current Approaches to Modeling the Receptor-G Protein Complex;86
5.3;III. Molecular Basis for G Protein Activation;89
5.4;IV. Summary and Conclusions;93
5.5;References;95
6;Chapter 3: Some Mechanistic Insights into GPCR Activation from Detergent-Solubilized Ternary Complexes on Beads;104
6.1;I. Perspectives;105
6.2;II. Survey of Experimental Approaches and Representative Data;108
6.2.1;A. Flow Cytometric Approaches to Assess GPCR Function In Vivo;108
6.2.2;B. Rapid Mix Flow Cytometry;109
6.2.3;C. Modular Assembly of Molecular Complexes on Beads;109
6.3;III. Analysis of Soluble Receptor Ternary Complex Assemblies;113
6.3.1;A. General Considerations;113
6.3.2;B. Simple Ternary Complex Model: General Considerations;114
6.3.3;C. Application of Ternary Complex Model;117
6.3.4;D. Landscapes of G-Bead Assemblies Based on Application of Experimentally Derived Binding Constants to the Ternary Complex Model;118
6.3.5;E. Ternary Complex Analysis of Soluble Receptor Assemblies;120
6.3.6;F. Are Unique Conformational Changes in Receptors Elicited by Interactions with Ligands Resulting in Varied G Protein Interactions by the Ligand-Bound Receptor?;124
6.4;IV. Guanine Nucleotide Activation of Ternary Complex: Some Dynamic Aspects of Structure and Reactivity;126
6.4.1;A. General Considerations;126
6.4.2;B. Structural Studies;127
6.4.3;C. Some Dynamic Aspects of GPCR Activation;128
6.4.4;D. Modular Disassembly of the Ternary Complexes: Guanine Nucleotide Activation Causes the Rapid Separation of the GPCR and Ligand from the G Protein;130
6.4.5;E. GDP Activity?;134
6.4.6;F. Galpha Subunit Dissociation?;135
6.4.7;G. Outlook;136
6.5;Acknowledgments;137
6.6;References;137
7;Chapter 4: Activation of G Protein-Coupled Receptors;146
7.1;I. Introduction;147
7.2;II. Structural and Mechanistic Homology Among GPCRs;149
7.2.1;A. Rhodopsin as a Structural Model for GPCRs;149
7.2.2;B. GPCRs Activated by Diffusible Agonists;150
7.2.3;C. GPCR Oligomers;151
7.3;III. Conformational States;152
7.3.1;A. Basal Activity and Ligand Efficacy;153
7.3.2;B. Multiple Agonist-Specific States;154
7.3.3;C. Defining the "Active State";155
7.4;IV. Activation by Agonists;157
7.4.1;A. Insights from Constitutively Active Mutants;157
7.4.2;B. Molecular Switches;159
7.4.3;C. Activation of Molecular Switches by Ligands;162
7.4.4;D. Agonist Binding and Activation Is a Multistep Process;164
7.4.5;E. The beta2AR as a Model System for Ligand Binding and Activation: Biophysical Analysis of Agonist-Induced Conformational Changes;164
7.5;V. Concluding Remarks;168
7.6;References;168
8;Chapter 5: Kinetic Analysis of G Protein-Coupled Receptor Signaling Using Fluorescence Resonance Energy Transfer in Living Cells;176
8.1;I. Introduction;176
8.2;II. Assays and Methods;179
8.2.1;A. Principle of the Assays;179
8.2.2;B. Construction and Expression of Fluorescent Receptor and G Protein Constructs;185
8.2.3;C. Microscopic FRET Measurements and Imaging;186
8.3;III. Results and Discussion;188
8.3.1;A. Agonist Binding;188
8.3.2;B. Receptor Activation;189
8.3.3;C. Receptor-G Protein Interaction;191
8.3.4;D. G Protein Activation;192
8.4;IV. Conclusions;193
8.5;Acknowledgments;194
8.6;References;194
9;Chapter 6: Regulation of Rho Guanine Nucleotide Exchange Factors by G Proteins;198
9.1;I. Introduction;199
9.1.1;A. Intrinsic Mechanisms of G Proteins;199
9.1.2;B. Regulation of Rho Proteins by Heterotrimeric G Proteins;202
9.2;II. RGS-RhoGEFs;202
9.2.1;A. Discovery and Relationships;202
9.2.2;B. The RGS Domain and GTPase Activity;205
9.2.3;C. The DH and PH Domains: Structure and Relative Activities;209
9.3;III. Mechanisms of Regulation;210
9.3.1;A. Direct Regulation of GEF Activity by G12 and G13;210
9.3.2;B. Indirect Regulation of RGS-RhoGEF Activity;212
9.3.3;C. Role of the C-Terminus in Oligomerization and Regulation of In Vivo Activity;214
9.3.4;D. Specificity of Regulation by G Proteins;215
9.3.5;E. Regulation of RGS-RhoGEFs by Phosphorylation;217
9.3.6;F. Function of the PDZ Domain;218
9.3.7;G. Expression of PDZ-RhoGEFs;222
9.4;IV. Physiological Function of the RGS-RhoGEFs;222
9.4.1;A. Pathway Specificity;223
9.4.2;B. Regulation in Hematopoietic Cells;223
9.4.3;C. Interactions with Other Proteins;225
9.5;Acknowledgments;230
9.6;References;230
10;Author Index;238
11;Subject Index;256