background:
Myotubularin-related protein 14 (MTMR14), also known as Jumpy, is a myotubularin-related phosphoinositol-3-phosphate (PI3P) phosphatase (1). Mutations in the MTMR14 gene have been associated with centronuclear myopathy (1). MTMR14 deficiency in mice leads to altered calcium homeostasis and muscle disorders (2). MTMR14 has also been shown to play a role in autophagy, a process that is highly regulated by phosphatidylinositides through the type III PI3K, Vps34 (3). MTMR14 was localized to autophagic isolation membranes and early autophagosomes (3). In these studies, MTMR14 inhibited autophagy and mutations of MTMR14 associated with centronuclear myopathy were also defective in autophagy inhibition. In zebrafish, MTMR14 knockdown was shown to increase the number of autophagosomes, suggesting that its activity is associated with an inhibition of autophagy (4).
Function:
Lipid phosphatase which efficiently dephosphorylates phosphatidylinositol 3-phosphate (PtdIns3P) and PtdIns(3,5)P2; inactive toward PtdIns4P, PtdIns(3,4)P2, PtdIns(4,5)P2 and PtdIns(3,4,5)P3.
Subunit:
Belongs to the protein-tyrosine phosphatase family. Non-receptor class myotubularin subfamily.
Subcellular Location:
Cytoplasm. Found in reticular structures and plasma membrane ruffles. Concentrated near the nucleus.
Tissue Specificity:
Expressed in various tissues, including heart, skeletal muscle, placenta, liver, lung, kidney and pancreas.
DISEASE:
Defects in MTMR14 may be a cause of centronuclear myopathy autosomal dominant (ADCNM) [MIM:160150]; also known as autosomal dominant myotubular myopathy. Centronuclear myopathies are congenital muscle disorders 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.
Similarity:
Belongs to the protein-tyrosine phosphatase family. Non-receptor class myotubularin subfamily.
Database links:
UniProtKB/Swiss-Prot: Q8NCE2.2
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
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