Myotubularins, a large disease-associated family of cooperating catalytically active and inactive phosphoinositides phosphatases.
The myotubularin family is a large eukaryotic group within the tyrosine/dual-specificity phosphatase super-family (PTP/DSP). Among the 14 human members, three are mutated in genetic diseases: myotubular myopathy and two forms of Charcot-Marie-Tooth neuropathy. We present an analysis of the myotubularin family in sequenced genomes. The myotubularin family encompasses catalytically active and inactive phosphatases, and both classes are well conserved from nematode to man. Catalytically active myotubularins dephosphorylate phosphatidylinositol 3-phosphate (PtdIns3P) and PtdIns3,5P2, leading to the production of PtdIns and PtdIns5P. This activity may be modulated by direct interaction with catalytically inactive myotubularins. These phosphoinositides are signaling molecules that are notably involved in vacuolar transport and membrane trafficking. Myotubularins are thus proposed to be implicated in these cellular mechanisms, and recent observations on myotubularins homologues in the nematode Caenorhabditis elegans indicate a role in endocytosis.
Laporte
Jocelyn
J
IGBMC, CNRS/INSERM.ULP, Illkirch, France.
Bedez
Florence
F
Bolino
Alessandra
A
Mandel
Jean-Louis
JL
D000595:Amino Acid Sequence; D002384:Catalysis; D019143:Evolution, Molecular; D030342:Genetic Diseases, Inborn / Q000235:genetics*; D006801:Humans; D010802:Phylogeny; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000378:metabolism*; D054558:Protein Tyrosine Phosphatases, Non-Receptor
D017027:Protein Tyrosine Phosphatases; D054558:Protein Tyrosine Phosphatases, Non-Receptor; C099588:myotubularin