![]() |
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
G-protein-coupled receptors (GPCRs) serve as catalytic activators of heterotrimeric G-proteins (G
β
) by exchanging GTP for the bound GDP on the G
subunit. This guanine nucleotide exchange factor activity of GPCRs is the initial step in the G-protein cycle and determines the onset of various intracellular signaling pathways that govern critical physiological responses to extracellular cues. Although the structural basis for many steps in the G-protein nucleotide cycle have been made clear over the past decade, the precise mechanism for receptor-mediated G-protein activation remains incompletely defined. Given that these receptors have historically represented a set of rich drug targets, a more complete understanding of their mechanism of action should provide further avenues for drug discovery. Several models have been proposed to explain the communication between activated GPCRs and G
β
leading to the structural changes required for guanine nucleotide exchange. This review is focused on the structural biology of G-protein signal transduction with an emphasis on the current hypotheses regarding G
β
activation. We highlight several recent results shedding new light on the structural changes in G
that may underlie GDP release.
Address correspondence to: Dr. David P. Siderovski, Department of Pharmacology, University of North Carolina at Chapel Hill, CB# 7365, Chapel Hill, NC 27599-7365. E-mail: dsiderov{at}med.unc.edu
This article has been cited by other articles:
![]() |
C. A. Johnston, K. Afshar, J. T. Snyder, G. G. Tall, P. Gonczy, D. P. Siderovski, and F. S. Willard Structural Determinants Underlying the Temperature-sensitive Nature of a G{alpha} Mutant in Asymmetric Cell Division of Caenorhabditis elegans J. Biol. Chem., August 1, 2008; 283(31): 21550 - 21558. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Altenbach, A. K. Kusnetzow, O. P. Ernst, K. P. Hofmann, and W. L. Hubbell From the Cover: High-resolution distance mapping in rhodopsin reveals the pattern of helix movement due to activation PNAS, May 27, 2008; 105(21): 7439 - 7444. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Soundararajan, F. S. Willard, A. J. Kimple, A. P. Turnbull, L. J. Ball, G. A. Schoch, C. Gileadi, O. Y. Fedorov, E. F. Dowler, V. A. Higman, et al. Structural diversity in the RGS domain and its interaction with heterotrimeric G protein {alpha}-subunits PNAS, April 29, 2008; 105(17): 6457 - 6462. [Abstract] [Full Text] [PDF] |
||||