A phosphatidylinositol-transfer protein and phosphatidylinositol-4-phosphate 5-kinase control Cdc42 to regulate the actin cytoskeleton and secretory pathway in yeast.

ABSTRACT: The actin cytoskeleton rapidly depolarizes in yeast secretory (sec) mutants at restrictive temperatures. Thus, an unknown signal conferred upon secretion is necessary for actin polarity and exocytosis. Here, we show that a phosphatidylinositol (PI) transfer protein, Sfh5, and a phosphatidylinositol-4-phosphate 5-kinase, Mss4, facilitate Cdc42 activation to concomitantly regulate both actin and protein trafficking. Defects in Mss4 function led to actin depolarization, an inhibition of secretion, reduced levels of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)] in membranes, mislocalization of a pleckstrin homology domain fused to green fluorescent protein, and the mislocalization of Cdc42. Similar defects were observed in sec, myo2-66, and cdc42-6 mutants at elevated temperatures and we

SUBMITTER: Yakir-Tamang L 

PROVIDER: S-EPMC2719576 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature