The function of Ensembl gene identifier ENSG00000104643 (MTMR9, myotubularin related protein 9) is as follows. Acts as an adapter for myotubularin-related phosphatases (PubMed:19038970, PubMed:22647598). Increases lipid phosphatase MTMR6 catalytic activity, specifically towards phosphatidylinositol 3,5- bisphosphate and MTMR6 binding affinity for phosphorylated phosphatidylinositols (PubMed:19038970, PubMed:22647598). Positively regulates lipid phosphatase MTMR7 catalytic activity (By similarity). Increases MTMR8 catalytic activity towards phosphatidylinositol 3- phosphate (PubMed:22647598). The formation of the MTMR6-MTMR9 complex, stabilizes both MTMR6 and MTMR9 protein levels (PubMed:19038970). Stabilizes MTMR8 protein levels (PubMed:22647598). Plays a role in the late stages of macropinocytosis possibly by regulating MTMR6-mediated dephosphorylation of phosphatidylinositol 3-phosphate in membrane ruffles (PubMed:24591580). Negatively regulates autophagy, in part via its association with MTMR8 (PubMed:22647598). Negatively regulates DNA damage-induced apoptosis, in part via its association with MTMR6 (PubMed:19038970, PubMed:22647598). Does not bind mono-, di- and tri- phosphorylated phosphatidylinositols, phosphatidic acid and phosphatidylserine (PubMed:19038970). {ECO:0000250|UniProtKB:Q9Z2D0, ECO:0000269|PubMed:19038970, ECO:0000269|PubMed:22647598, ECO:0000269|PubMed:24591580}.