MTMR9
Description
The MTMR9 (myotubularin related protein 9) is a protein-coding gene located on chromosome 8.
Myotubularin-related protein 9 (MTMR9) is a protein encoded by the MTMR9 gene in humans. It is atypical among myotubularin-related proteins as it lacks a dual-specificity phosphatase domain. MTMR9 contains a double-helical motif similar to the SET interaction domain, which is thought to be involved in regulating cell proliferation. In mice, a protein similar to MTMR9 binds with MTMR7, and together they dephosphorylate phosphatidylinositol 3-phosphate and inositol 1,3-bisphosphate. MTMR9 has been shown to interact with MTMR6.
MTMR9 acts as an adapter protein for other myotubularin-related phosphatases. It increases the catalytic activity of MTMR6, specifically toward phosphatidylinositol 3,5-bisphosphate, and enhances MTMR6's binding affinity for phosphorylated phosphatidylinositols. Additionally, MTMR9 positively regulates MTMR7 catalytic activity and increases MTMR8 catalytic activity towards phosphatidylinositol 3-phosphate. The formation of the MTMR6-MTMR9 complex stabilizes the protein levels of both MTMR6 and MTMR9. It also stabilizes MTMR8 protein levels. MTMR9 plays a role in the late stages of macropinocytosis, possibly by regulating MTMR6-mediated dephosphorylation of phosphatidylinositol 3-phosphate in membrane ruffles. It negatively regulates autophagy, partly through its association with MTMR8, and negatively regulates DNA damage-induced apoptosis, partly through its association with MTMR6. MTMR9 does not bind to mono-, di-, or tri-phosphorylated phosphatidylinositols, phosphatidic acid, or phosphatidylserine.
MTMR9 is also known as C8orf9, LIP-STYX, MTMR8.
Associated Diseases
- Parkinson disease
- multiple sclerosis
- Alzheimer disease
- lysosomal storage disease
- spinocerebellar ataxia type 20
- spinocerebellar ataxia type 23
- spinocerebellar ataxia type 15/16
