Phosphatase that acts on lipids with a phosphoinositol headgroup (, ). Dephosphorylates phosphatidylinositol 3-phosphate (PtdIns(3)P) and phosphatidylinositol 3,5-bisphosphate (, ) (Probable). Binds with high affinity to phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2) but also to phosphatidylinositol 3-phosphate (PtdIns(3)P), phosphatidylinositol 4-phosphate (PtdIns(4)P), and phosphatidylinositol 5-phosphate (PtdIns(5)P), phosphatidic acid and phosphatidylserine . Negatively regulates ER-Golgi protein transport (By similarity). Probably in association with MTMR9, plays a role in the late stages of macropinocytosis by dephosphorylating phosphatidylinositol 3-phosphate in membrane ruffles . Acts as a negative regulator of KCNN4/KCa3.1 channel activity in CD4(+) T-cells possibly by decreasing intracellular levels of phosphatidylinositol 3-phosphate . Negatively regulates proliferation of reactivated CD4(+) T-cells . In complex with MTMR9, negatively regulates DNA damage-induced apoptosis (, ). The formation of the MTMR6-MTMR9 complex stabilizes both MTMR6 and MTMR9 protein levels .
Subcellular locations: Cytoplasm, Endoplasmic reticulum-Golgi intermediate compartment, Endoplasmic reticulum, Cell projection, Ruffle membrane, Cytoplasm, Perinuclear region
Localizes to ruffles during EGF-induced macropinocytosis (By similarity). Colocalizes with MTMR9 to the perinuclear region . Partially localizes to the endoplasmic reticulum . Co-localizes with RAB1B to the endoplasmic reticulum-Golgi intermediate compartment and to the peri-Golgi region (By similarity).
Expressed in CD4+ T-cells.