Characterization of a 54-kilodalton human protein kinase recognized by an antiserum raised against the myotonin kinase
✍ Scribed by Pierre Etongué-Mayer; Robert Faure; Jean-Pierre Bouchard; Jack Puymirat
- Book ID
- 101249445
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 242 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0148-639X
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✦ Synopsis
We characterized a 54-kDa human protein kinase recognized by an antiserum raised against the human myotonin protein kinase. This protein kinase displays a serine/threonine kinase activity in the heart and a tyrosine kinase activity in the skeletal muscle. Both kinase activities were attributed to the same 54-kDa protein based on the identity of onedimensional peptide maps. We showed that the tyrosine kinase activity observed in the skeletal muscle results from a phosphorylation of this protein kinase on tyrosine residues by a tyrosine kinase specifically expressed in this tissue. The tyrosine dephosphorylation of the skeletal muscle 54-kDa protein kinase allowed it to phosphorylate with the highest activity the same peptide substrates as those phosphorylated by the human recombinant myotonin kinase. These results show that a muscle-specific tyrosine phosphorylation event converts a serine/threonine kinase to a tyrosine kinase. They also suggest that the 54-kDa protein kinase is a member of the myotonin kinase family.