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Posttranscriptional regulation of the glycerophosphoinositol/glycerophosphocholine transporter of Saccharomyces cerevisiae
Author(s) -
PattonVogt Jana,
Almaguer Claudia
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a952-a
Subject(s) - saccharomyces cerevisiae , downregulation and upregulation , transcription (linguistics) , transporter , microbiology and biotechnology , biochemistry , phosphatidylinositol , biology , proteolysis , phosphatidylcholine , chemistry , yeast , signal transduction , gene , membrane , phospholipid , enzyme , linguistics , philosophy
Phospholipase‐B mediated deacylation of phosphatidylinositol and phosphatidylcholine results in the formation of glycerophosphoinositol (GroPIns) and glycerophosphocholine (GroPCho), respectively. GroPIns and GroPCho are transported across the Saccharomyces cerevisiae plasma membrane into the cell via the transporter encoded by GIT1. Previous studies have shown that GIT1 expression is regulated by phosphate availability through the transcription factors Pho2p and Pho4p. We now report that posttranscriptional mechanisms also regulate Git1p activity in response to phosphate availability. Mutations that inhibit endocytosis and vacuolar proteolysis also inhibit Git1p degradation in high phosphate medium, indicating that Git1p is internalized before being degraded in the vacuole. Git1p substrates, GroPIns and GroPCho, also downregulate Git1p activity via posttranscriptional mechanisms, but, interestingly, do not repress GIT1 transcription. These results indicate that Git1p transport activity is regulated at multiple levels. This research was supported by NIH grant GM59817 to J.P.‐V.