Phosphatase Family Myotubularin

Phosphatase Classification: FoldCC1: Superfamily CC1: Family Myotubularin

Myotubularins are 3-phosphatases specific for PtdIns3P and PtdIns(3,5)P2, two PIs that function within the endosomal-lysomal pathway . In yeast, there is a single myotubularin Ymr1p, and its functions appear to be redundant with those of other 3-phosphatases. In C. elegans, which has six myotubularins, several of the myotublarins have non-redundant roles in regulating PtdIns3P during endocytosis. In human, there are 14 myotublarins, and mutations in several of them lead to myotubular myopathy and Charcot-Marie-Tooth peripheral neuropathy. Interestingly, around half of myotubularins are catalytically inactive. One of their possible function is regulating active myotubularins by protein interaction. For details, see the review [1].

Subfamilies

MTMR5 (SBF)

Inactive myotubularin subfamily.

YMR1

Yeast has a single myotubularin YMR1, encoding PI(3)P phosphatase [2].

Reference

1. Robinson FL and Dixon JE. Myotubularin phosphatases: policing 3-phosphoinositides. Trends Cell Biol. 2006 Aug;16(8):403-12. DOI:10.1016/j.tcb.2006.06.001 |
2. Taylor GS, Maehama T, and Dixon JE. Myotubularin, a protein tyrosine phosphatase mutated in myotubular myopathy, dephosphorylates the lipid second messenger, phosphatidylinositol 3-phosphate. Proc Natl Acad Sci U S A. 2000 Aug 1;97(16):8910-5. DOI:10.1073/pnas.160255697 |