MTMR9

This gene encodes a myotubularin-related protein that is atypical to most other members of the myotubularin-related protein family because it has no dual-specificity phosphatase domain. The encoded protein contains a double-helical motif similar to the SET interaction domain, which is thought to have a role in the control of cell proliferation. In mouse, a protein similar to the encoded protein binds with MTMR7, and together they dephosphorylate phosphatidylinositol 3-phosphate and inositol 1,3-bisphosphate. [provided by RefSeq]

Full Name

myotubularin related protein 9

Function

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).

Biological Process

Endocytosis Source: UniProtKB-KW
Negative regulation of autophagy Source: UniProtKB
Phosphatidylinositol dephosphorylation Source: GO_Central
Positive regulation of phosphatase activity Source: UniProtKB
Protein stabilization Source: UniProtKB
Regulation of phosphatidylinositol dephosphorylation Source: UniProtKB

Cellular Location

Endoplasmic reticulum
Cytoplasm
Plasma membrane
ruffle membrane
Other locations
perinuclear region
Note: Localizes to ruffles during EGF-induced macropinocytosis (By similarity). Colocalizes with MTMR6 to the perinuclear region (PubMed:19038970). Partially localizes to the endoplasmic reticulum (PubMed:19038970).