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J Biol Chem

Title:		Feedback phosphorylation of an RGS protein by MAP kinase in yeast
Author(s):		Garrison TR; Zhang Y; Pausch M; Apanovitch D; Aebersold R; Dohlman HG;
Address:		"Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06536, USA"
Journal Title:		J Biol Chem
Year:		1999
Volume:		274
Issue:		51
Page Number:		36387 - 36391
DOI:		10.1074/jbc.274.51.36387
ISSN/ISBN:		0021-9258 (Print) 0021-9258 (Linking)
Abstract:		"Regulators of G protein signaling (RGS proteins) are well known to accelerate G protein GTPase activity in vitro and to promote G protein desensitization in vivo. Less is known about how RGS proteins are themselves regulated. To address this question we purified the RGS in yeast, Sst2, and used electrospray ionization mass spectrometry to identify post-translational modifications. This analysis revealed that Sst2 is phosphorylated at Ser-539 and that phosphorylation occurs in response to pheromone stimulation. Ser-539 lies within a consensus mitogen-activated protein (MAP) kinase phosphorylation site, Pro-X-Ser-Pro. Phosphorylation is blocked by mutations in the MAP kinase genes (FUS3, KSS1), as well as by mutations in components needed for MAP kinase activation (STE11, STE7, STE4, STE18). Phosphorylation is also blocked by replacing Ser-539 with Ala, Asp, or Glu (but not Thr). These point mutations do not alter pheromone sensitivity, as determined by growth arrest and reporter transcription assays. However, phosphorylation appears to slow the rate of Sst2 degradation. These findings indicate that the G protein-regulated MAP kinase in yeast can act as a feedback regulator of Sst2, itself a regulator of G protein signaling"
Keywords:		Amino Acid Sequence Feedback MAP Kinase Signaling System Mitogen-Activated Protein Kinases/*metabolism Molecular Sequence Data Phosphorylation RGS Proteins/*metabolism Saccharomyces cerevisiae/*physiology Signal Transduction/*physiology;
Notes:		"MedlineGarrison, T R Zhang, Y Pausch, M Apanovitch, D Aebersold, R Dohlman, H G eng R01 GM055316/GM/NIGMS NIH HHS/ R01 GM059167/GM/NIGMS NIH HHS/ GM59167/GM/NIGMS NIH HHS/ GM55316/GM/NIGMS NIH HHS/ RR11823/RR/NCRR NIH HHS/ Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. 1999/12/14 J Biol Chem. 1999 Dec 17; 274(51):36387-91. doi: 10.1074/jbc.274.51.36387"