Phosphatidylinositol polyphosphate 5 phosphatase type IV
Phosphatidylinositol polyphosphate 5-phosphatase type IV
Converts phosphatidylinositol 3,4,5-trisphosphate (PtdIns 3,4,5-P3) to PtdIns-P2. Specific for lipid substrates, inactive towards water soluble inositol phosphates.
Detected in brain, heart, pancreas, testis and spleen.
Involvement in disease
Defects in INPP5E are the cause of Joubert syndrome type 1 (JBTS1) [MIM:213300]. A disorder presenting with cerebellar ataxia, oculomotor apraxia, hypotonia, neonatal breathing abnormalities and psychomotor delay. Neuroradiologically, it is characterized by cerebellar vermian hypoplasia/aplasia, thickened and reoriented superior cerebellar peduncles, and an abnormally large interpeduncular fossa, giving the appearance of a molar tooth on transaxial slices (molar tooth sign). Additional variable features include retinal dystrophy and renal disease. Defects in INPP5E are the cause of mental retardation-truncal obesity-retinal dystrophy-micropenis (MORMS) [MIM:610156]. An autosomal recessive disorder characterized by moderate mental retardation, truncal obesity, congenital non-progressive retinal dystrophy, and micropenis in males. The phenotype is similar to Bardet-Biedl syndrome and Cohen syndrome Distinguishing features are the age of onset, the non-progressive nature of the visual impairment, lack of dysmorphic facies, skin or gingival infection, microcephaly, mottled retina, polydactyly, and testicular anomalies.
Belongs to the inositol 1,4,5-trisphosphate 5-phosphatase type IV family.
Phosphorylated upon DNA damage, probably by ATM or ATR.
Cytoplasm > cytoskeleton > cilium axoneme. Golgi apparatus > Golgi stack membrane. Peripheral membrane protein associated with Golgi stacks.