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Characterization of a 54‐kilodalton human protein kinase recognized by an antiserum raised against the myotonin kinase
Author(s) -
EtonguéMayer Pierre,
Faure Robert,
Bouchard JeanPierre,
Puymirat Jack
Publication year - 1998
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199801)21:1<8::aid-mus2>3.0.co;2-g
Subject(s) - map2k7 , mitogen activated protein kinase kinase , cyclin dependent kinase 9 , map kinase kinase kinase , cyclin dependent kinase 2 , ask1 , tyrosine kinase , c raf , biology , biochemistry , protein kinase a , microbiology and biotechnology , chemistry , phosphorylation , signal transduction
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 one‐dimensional 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. © 1998 John Wiley & Sons, Inc. Muscle Nerve, 21: 8–17, 1998.