Inositol polyphosphate-4-phosphatase type I A
Function
Catalyzes the hydrolysis of the 4-position phosphate of phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4)P2) (PubMed:15716355, PubMed:20463662). Catalyzes also inositol 1,3,4-trisphosphate and inositol 1,4-bisphosphate (By similarity). Antagonizes the PI3K-AKT/PKB signaling pathway by dephosphorylating phosphoinositides and thereby modulating cell cycle progression and cell survival (By similarity) (PubMed:30071275). May protect neurons from excitotoxic cell death by regulating the synaptic localization of cell surface N-methyl-D-aspartate-type glutamate receptors (NMDARs) and NMDAR-mediated excitatory postsynaptic current (By similarity).
Isoform 4
Displays no 4-phosphatase activity for PtdIns(3,4)P2, Ins(3,4)P2, or Ins(1,3,4)P3.
Pathway
Signal transduction; phosphatidylinositol signaling pathway.
Sequence Similarities
Belongs to the inositol 3,4-bisphosphate 4-phosphatase family.
Tissue Specificity
Isoform 1 is expressed in the platelets, MEG-01 megakaryocytes and Jurkat T-cells. Isoform 2 is expressed in the brain.
Cellular localization
- Early endosome membrane
- Recycling endosome membrane
- Cell membrane
- Nucleus
- Cytoplasm
- Postsynaptic density
- Translocates to the plasma membrane upon EGF stimulation (PubMed:15716355). Shuttles between the cytoplasm and the nucleus, depending on the cell cycle stage, with highest amounts detected in the nucleus during the G0/G1phase (PubMed:30071275).
Alternative names
Inositol polyphosphate-4-phosphatase type I A, Inositol polyphosphate 4-phosphatase type I, INPP4A