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Mol Biol Cell

Title:		An essential role of the yeast pheromone-induced Ca2+ signal is to activate calcineurin
Author(s):		Withee JL; Mulholland J; Jeng R; Cyert MS;
Address:		"Department of Biological Sciences, Stanford University, California 94305-5020, USA"
Journal Title:		Mol Biol Cell
Year:		1997
Volume:		8
Issue:		2
Page Number:		263 - 277
DOI:		10.1091/mbc.8.2.263
ISSN/ISBN:		1059-1524 (Print) 1059-1524 (Linking)
Abstract:		"Previous studies showed that, in wild-type (MATa) cells, alpha-factor causes an essential rise in cytosolic Ca2+. We show that calcineurin, the Ca2+/calmodulin-dependent protein phosphatase, is one target of this Ca2+ signal. Calcineurin mutants lose viability when incubated with mating pheromone, and overproduction of constitutively active (Ca(2+)-independent) calcineurin improves the viability of wild-type cells exposed to pheromone in Ca(2+)-deficient medium. Thus, one essential consequence of the pheromone-induced rise in cytosolic Ca2+ is activation of calcineurin. Although calcineurin inhibits intracellular Ca2+ sequestration in yeast cells, neither increased extracellular Ca2+ nor defects in vacuolar Ca2+ transport bypasses the requirement for calcineurin during the pheromone response. These observations suggest that the essential function of calcineurin in the pheromone response may be distinct from its modulation of intracellular Ca2+ levels. Mutants that do not undergo pheromone-induced cell cycle arrest (fus3, far1) show decreased dependence on calcineurin during treatment with pheromone. Thus, calcineurin is essential in yeast cells during prolonged exposure to pheromone and especially under conditions of pheromone-induced growth arrest. Ultrastructural examination of pheromone-treated cells indicates that vacuolar morphology is abnormal in calcineurin-deficient cells, suggesting that calcineurin may be required for maintenance of proper vacuolar structure or function during the pheromone response"
Keywords:		Biological Transport Calcineurin Calcium/*pharmacology Calmodulin-Binding Proteins/genetics/*metabolism Cell Cycle Cell Wall Culture Media Enzyme Activation Mating Factor Mutation Peptides/*pharmacology Pheromones/*pharmacology Phosphoprotein Phosphatases;
Notes:		"MedlineWithee, J L Mulholland, J Jeng, R Cyert, M S eng 5 T32 GM-7276/GM/NIGMS NIH HHS/ GM-46406/GM/NIGMS NIH HHS/ GM-48729/GM/NIGMS NIH HHS/ Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. 1997/02/01 Mol Biol Cell. 1997 Feb; 8(2):263-77. doi: 10.1091/mbc.8.2.263"