« Previous AbstractUtilization of the mating scaffold protein in the evolution of a new signal transduction pathway for biofilm development    Next AbstractSlow food: insect prey and chitin induce phytohormone accumulation and gene expression in carnivorous Nepenthes plants »

Proc Natl Acad Sci U S A

Title:		A quantitative characterization of the yeast heterotrimeric G protein cycle
Author(s):		Yi TM; Kitano H; Simon MI;
Address:		"Systems Biology Group, Exploratory Research for Advanced Technology Kitano Symbiotic Systems Project, Japan Science and Technology Corporation, Shibuya, Tokyo, Japan"
Journal Title:		Proc Natl Acad Sci U S A
Year:		2003
Volume:		20030905
Issue:		19
Page Number:		10764 - 10769
DOI:		10.1073/pnas.1834247100
ISSN/ISBN:		0027-8424 (Print) 1091-6490 (Electronic) 0027-8424 (Linking)
Abstract:		"The yeast mating response is one of the best understood heterotrimeric G protein signaling pathways. Yet, most descriptions of this system have been qualitative. We have quantitatively characterized the heterotrimeric G protein cycle in yeast based on direct in vivo measurements. We used fluorescence resonance energy transfer to monitor the association state of cyan fluorescent protein (CFP)-Galpha and Gbetagamma-yellow fluorescent protein (YFP), and we found that receptor-mediated G protein activation produced a loss of fluorescence resonance energy transfer. Quantitative time course and dose-response data were obtained for both wild-type and mutant cells possessing an altered pheromone response. These results paint a quantitative portrait of how regulators such as Sst2p and the C-terminal tail of alpha-factor receptor modulate the kinetics and sensitivity of G protein signaling. We have explored critical features of the dynamics including the rapid rise and subsequent decline of active G proteins during the early response, and the relationship between the G protein activation dose-response curve and the downstream dose-response curves for cell-cycle arrest and transcriptional induction. Fitting the data to a mathematical model produced estimates of the in vivo rates of heterotrimeric G protein activation and deactivation in yeast"
Keywords:		Energy Transfer Fluorescence Heterotrimeric GTP-Binding Proteins/*metabolism Kinetics Mating Factor Peptides/metabolism Saccharomyces cerevisiae/*metabolism *Signal Transduction;
Notes:		"MedlineYi, Tau-Mu Kitano, Hiroaki Simon, Melvin I eng Research Support, Non-U.S. Gov't 2003/09/10 Proc Natl Acad Sci U S A. 2003 Sep 16; 100(19):10764-9. doi: 10.1073/pnas.1834247100. Epub 2003 Sep 5"