INPP5B
Domain
The ASH (ASPM-SPD2-Hydin) and RhoGAP (Rho GTPase activating) domains form a single folding module. The ASH domain has an immunoglobulin-like fold, the Rho-GAP domain lacks the catalytic arginine and is catalytically inactive. The ASH-RhoGAP module regulates the majority of the protein-protein interactions currently described. The ASH domain mediates association with membrane-targeting Rab GTPases. The Rho-GAP domain interacts with the endocytic adapter APPL1, which is then displaced by FAM109A and FAM109B as endosomes mature, all three interactions rely on F&H motifs, an approximately 12-13 amino-acid sequence centered around Phe and His residues essential for binding (By similarity).
Function
Hydrolyzes phosphatidylinositol 4,5-bisphosphate (PtIns(4,5)P2) and the signaling molecule phosphatidylinositol 1,4,5-trisphosphate (PtIns(1,4,5)P3), and thereby modulates cellular signaling events.
Post-translational modifications
Isoprenylation at Cys-990 may be required for localization at the membrane.
May be proteolytically cleaved after Lys-320 as inferred from N-terminal protein sequence of the 75 kda form.
Sequence Similarities
Belongs to the inositol 1,4,5-trisphosphate 5-phosphatase type II family.
Tissue Specificity
Platelets.
Cellular localization
- Cytoplasm
- Cytosol
- Endoplasmic reticulum-Golgi intermediate compartment
- Early endosome membrane
- Membrane
- Peripheral membrane protein
- Cytoplasmic side
- Cytoplasmic vesicle
- Phagosome membrane
- Golgi apparatus
Alternative names
OCRL2, INPP5B, 75 kDa inositol polyphosphate-5-phosphatase, Phosphoinositide 5-phosphatase, 5PTase