Assembly of a Fab1 phosphoinositide kinase signaling complex requires the Fig4 phosphoinositide phosphatase.

ABSTRACT: Phosphatidylinositol-3,5-bisphosphate [PtdIns(3,5)P(2)] regulates several vacuolar functions, including acidification, morphology, and membrane traffic. The lipid kinase Fab1 converts phosphatidylinositol-3-phosphate [PtdIns(3)P] to PtdIns(3,5)P(2). PtdIns(3,5)P(2) levels are controlled by the adaptor-like protein Vac14 and the Fig4 PtdIns(3,5)P(2)-specific 5-phosphatase. Interestingly, Vac14 and Fig4 serve a dual function: they are both implicated in the synthesis and turnover of PtdIns(3,5)P(2) by an unknown mechanism. We now show that Fab1, through its chaperonin-like domain, binds to Vac14 and Fig4 and forms a vacuole-associated signaling complex. The Fab1 complex is tethered to the vacuole via an interaction between the FYVE domain in Fab1 and PtdIns(3)P on the vacuole. Moreover, Vac1

SUBMITTER: Botelho RJ 

PROVIDER: S-EPMC2555960 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature