FEATURES

DESCRIPTION

Also known as FIG4_HUMAN, FIG4, KIAA0274, SAC3. Dual specificity phosphatase component of the PI(3, 5)P2 regulatory complex which regulates both the synthesis and turnover of phosphatidylinositol 3, 5-bisphosphate (PtdIns(3, 5)P2) (PubMed:17556371, PubMed:33098764). Catalyzes the dephosphorylation of phosphatidylinositol 3, 5-bisphosphate (PtdIns(3, 5)P2) to form phosphatidylinositol 3-phosphate (PubMed:33098764). Has serine-protein phosphatase activity acting on PIKfyve to stimulate its lipid kinase activity, its catalytically activity being required for maximal PI(3, 5)P2 production (PubMed:33098764). In vitro, hydrolyzes all three D5-phosphorylated polyphosphoinositide and although displaying preferences for PtdIns(3, 5)P2, it is capable of hydrolyzing PtdIns(3, 4, 5)P3 and PtdIns(4, 5)P2, at least in vitro (PubMed:17556371). Component of the PI(3, 5)P2 regulatory complex/PAS complex, at least composed of PIKFYVE, FIG4 and VAC14. VAC14 nucleates the assembly of the complex and serves as a scaffold by pentamerizing into a star-shaped structure, which can bind a single copy each of PIKFYVE and FIG4 and coordinates their activities.

EXTERNAL LINKS

FIG4

Polyphosphoinositide phosphatase

FIG4

Molecular Synopsis