A quantitative characterization of the yeast heterotrimeric G protein cycle
- Creators
- Yi, Tau-Mu
- Kitano, Hiroaki
- Simon, Melvin I.
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 a-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.
Additional Information
© 2003 by the National Academy of Sciences. Contributed by Melvin I. Simon, July 14, 2003. Published online before print September 5, 2003, 10.1073/pnas.1834247100 We thank Drs. Ray Deshaies and Chris Rao for critical reading of the manuscript; the Deshaies laboratory for yeast strains and vectors; and the Simon laboratory for valuable discussions. This work was supported by the Exploratory Research for Advanced Technology Kitano Symbiotic Systems Project of the Japanese Science and Technology Corporation.Attached Files
Published - YITpnas03.pdf
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Additional details
- PMCID
- PMC196877
- Eprint ID
- 1111
- Resolver ID
- CaltechAUTHORS:YITpnas03
- Japan Science and Technology Agency
- Created
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2005-12-20Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field