Myotubularin and the myotubularin-related proteins (MTMR1-9) belong to a highly conserved family of eukaryotic phosphatases. They are protein tyrosine phosphatases that utilize inositol phospholipids, rather than phosphoproteins, as substrates. MTMR family members hydrolyze both phosphatidylinositol 3-phosphate (PtdIns3P) and PtdIns(3,5)P2. MTMR2 interacts with MTMR5, an inactive family member that increases the enzymatic activity of MTMR2 and dictates its subcellular localization. Mutations in MTMR2 cause autosomal recessive Charcot-Marie-Tooth type 4B1 (CMT4B1), which is characterized by reduced nerve conduction velocities, focally folded myelin sheaths and demyelination. MTMR3 and MTMR4 can either interact with each other or self-associate. MTMR6 regulates the activity of the calcium-activated potassium channel 3.1. MTMR9 regulates the activity of MTMR7 and MTMR8
Function:
Phosphatase that acts on lipids with a phosphoinositol headgroup. Acts as a negative regulator of KCNN4/KCa3.1 channel activity in CD4+ T-cells possibly by decreasing intracellular levels of phosphatidylinositol-3 phosphatase. Negatively regulates proliferation of reactivated CD4+ T-cells.
Subcellular Location:
Nucleus envelope.
Tissue Specificity:
Expressed in CD4+ T-cells.
Similarity:
Belongs to the protein-tyrosine phosphatase family. Non-receptor class myotubularin subfamily.
Contains 1 myotubularin phosphatase domain.
SWISS:
Q9Y217
Gene ID:
9107
Database links:
Entrez Gene: 9107 Human
Omim: 603561 Human
SwissProt: Q9Y217 Human
Unigene: 643702 Human
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