PIKFYVE, KIAA0981, PIP5K3, 1-phosphatidylinositol 3-phosphate 5-kinase, Phosphatidylinositol 3-phosphate 5-kinase, FYVE finger-containing phosphoinositide kinase, PIKfyve, Phosphatidylinositol 3-phosphate 5-kinase type III, PIPkin-III, Type
Phosphorylated derivatives of phosphatidylinositol (PtdIns) regulate cytoskeletal functions, membrane trafficking, and receptor signaling by recruiting protein complexes to cell- and endosomal-membranes. Humans have multiple PtdIns proteins that differ by the degree and position of phosphorylation of the inositol ring. This gene encodes an enzyme (PIKfyve, also known as phosphatidylinositol-3-phosphate 5-kinase type III or PIPKIII) that phosphorylates the D-5 position in PtdIns and phosphatidylinositol-3-phosphate (PtdIns3P) to make PtdIns5P and PtdIns(3,5)biphosphate. The D-5 position also can be phosphorylated by type I PtdIns4P-5-kinases (PIP5Ks) that are encoded by distinct genes and preferentially phosphorylate D-4 phosphorylated PtdIns. In contrast, PIKfyve preferentially phosphorylates D-3 phosphorylated PtdIns. In addition to being a lipid kinase, PIKfcatalytic activity:ATP + 1-phosphatidyl-1D-myo-inositol 4-phosphate = ADP + 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate.,disease:Defects in PIKFYVE are the cause of corneal fleck dystrophy (CFD) [MIM:121850]. CFD is an autosomal dominant disorder of the cornea characterized by numerous small white flecks scattered in all levels of the stroma. Although CFD may occasionally cause mild photophobia, patients are typically asymptomatic and have normal vision.,function:Supports the intracellular PIP pool and to a lesser extent, the PI 4,5-P(2) pool. It generates PIP from PI and, to a lesser extent, PI 4,5-P(2) from PI 4-P. There are indications that it phosphorylates the D-5 rather than the D-4 position. Has a role in endosome-related membrane trafficking.,similarity:Contains 1 DEP domain.,similarity:Contains 1 FYVE-type zinc finger.,similarity:Contains 1 PI5K domain.,subcellular location:Mainly associated with membranes of the late endocytic pathway.,
