MTM1
Domain
The GRAM domain mediates binding to PI(3,5)P2 and, with lower affinity, to other phosphoinositides.
Function
Lipid phosphatase which dephosphorylates phosphatidylinositol 3-monophosphate (PI3P) and phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) (PubMed:10900271, PubMed:11001925, PubMed:12646134, PubMed:14722070). Has also been shown to dephosphorylate phosphotyrosine- and phosphoserine-containing peptides (PubMed:9537414). Negatively regulates EGFR degradation through regulation of EGFR trafficking from the late endosome to the lysosome (PubMed:14722070). Plays a role in vacuolar formation and morphology. Regulates desmin intermediate filament assembly and architecture (PubMed:21135508). Plays a role in mitochondrial morphology and positioning (PubMed:21135508). Required for skeletal muscle maintenance but not for myogenesis (PubMed:21135508). In skeletal muscles, stabilizes MTMR12 protein levels (PubMed:23818870).
Involvement in disease
Myopathy, centronuclear, X-linked
CNMX
A congenital muscle disorder characterized by progressive muscular weakness and wasting involving mainly limb girdle, trunk, and neck muscles. It may also affect distal muscles. Weakness may be present during childhood or adolescence or may not become evident until the third decade of life. Ptosis is a frequent clinical feature. The most prominent histopathologic features include high frequency of centrally located nuclei in muscle fibers not secondary to regeneration, radial arrangement of sarcoplasmic strands around the central nuclei, and predominance and hypotrophy of type 1 fibers.
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the protein-tyrosine phosphatase family. Non-receptor class myotubularin subfamily.
Cellular localization
- Cytoplasm
- Cell membrane
- Peripheral membrane protein
- Cell projection
- Filopodium
- Cell projection
- Ruffle
- Late endosome
- Cytoplasm
- Myofibril
- Sarcomere
- Localizes as a dense cytoplasmic network (PubMed:11001925). Also localizes to the plasma membrane, including plasma membrane extensions such as filopodia and ruffles (PubMed:12118066). Predominantly located in the cytoplasm following interaction with MTMR12 (PubMed:12847286). Recruited to the late endosome following EGF stimulation (PubMed:14722070). In skeletal muscles, co-localizes with MTMR12 in the sarcomere (By similarity).
Alternative names
CG2, MTM1, Myotubularin, Phosphatidylinositol-3-phosphate phosphatase