INPP5E (inositol polyphosphate 5-phosphatase), also known as hosphatidylinositol polyphosphate 5-phosphatase type IV, is a 644 amino acid peripheral membrane protein associated with Golgi stacks. Belonging to the inositol-1,4,5-trisphosphate 5-phosphatase type IV family, INPP5E converts phosphatidylinositol-3,4,5-triphosphate (PtdIns 3,4,5-P3) to PtdIns-P2. While inactive towards water soluble inositol phosphates, the activity of INPP5E is specific for lipid substrates. INPP5E becomes phosphorylated upon DNA damage and is expressed in brain, heart, pancreas, testis and spleen. Defects in INPP5E are the cause of Joubert syndrome type 1 (JBTS1), a disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. In addition, mutations in the INPP5E gene may lead to mental retardation-truncal obesity-retinal dystrophy-micropenis (MORMS), an autosomal recessive disorder characterized by moderate mental retardation, truncal obesity, congenital non-progressive retinal dystrophy, and micropenis in males.
5-bisphosphate 5-phosphatase; 5-phosphatase that induces arborization; 72 kDa inositol polyphosphate 5-phosphatase; inositol polyphosphate 5-phosphatase; inositol polyphosphate-5-phosphatase, 72 kDa; pharbin; Phosphatidylinositol 4; Phosphatidylinositol 4,5-bisphosphate 5-phosphatase; Phosphatidylinositol polyphosphate 5-phosphatase type IV; phosphatidylinositol-4,5-bisphosphate 5-phosphatase