※ Myotubularins family introduction

    Myotubularins (MTM) phosphatases belong to a family of conserved DUSP phosphatase. The myotubularins is consist of 14 members which share a conserved protein tyrosine phosphatase catalytic domain and myotubularins is a large family of phosphoinositide lipid 3-phosphatases with specificity for PtdIns3P and PtdIns (3, 5) P2. Besides PTP domain, myotubularins also contains other motifs which may contribute to protein−protein or protein−lipid interactions. Myotubularins participates in endocytic pathway by regulating substrates PtdIns3P and PtdIns (3,5)P2 which are key regulator of endocytic pathway and myotubularins may function to suppress concentration of substrate lipids at inappropriate compartments. In addition, some studies show that several MTMs, such as MTMR1, MTMR6, MTMR7, MTMR8 and MTMR12 play an important role in promoting cell survival by regulating PtdIns5P level and PtdIns (3,4,5)P3 specific 5-phosphatase, in turn control PKB/Akt activation. Myotubularins mutation is often accompanied with some diseases. MTM1 mutation can lead to condition known as myotubular myopathy. MTMR2 and MTMR13/Sbf2 mutations lead to clinically indistinguishable forms of a neuropathy called Charcot−Marie−Tooth syndrome (types 4B1 and 4B2). MTMR2 and MTMR5/Sbf1 mutations lead to impaired spermatogenesis and azoospermia.

Reference
1. Clague, M.J. and Lorenzo, O. (2005) The myotubularin family of lipid phosphatases. Traffic, 6, 1063-1069. PMID: 16262718