Activation of microtubule-associated protein kinase by microtubule disruption in quiescent rat 3Y1 cells.
Treatment of quiescent rat fibroblastic cells (3Y1) with colchicine, a microtubule-disrupting agent, which could induce the initiation of DNA synthesis [Y. Shinohara, E. Nishida, and H. Sakai (1989) Eur. J. Biochem. 183, 275-280], activated a serine/threonine-specific protein kinase activity in cell extracts that preferentially phosphorylated exogenous microtubule-associated protein 2 (MAP2). Vinblastine treatment also activated the kinase activity, and taxol pretreatment inhibited the colchicine-induced activation of this kinase activity. The detailed biochemical characterization indicated that this microtubule disruption-activated MAP2 kinase was very similar or identical to the mitogen-activated MAP kinase in the substrate specificity and chromatographic behaviors on phosphocellulose, DEAE-cellulose, gel filtration, and phenyl-Sepharose. Pretreatment of the cells with protein synthesis inhibitors did not prevent the MAP2 kinase activation by colchicine. Moreover, phosphatase treatment inactivated the colchicine-activated MAP2 kinase activity. These data suggest that microtubule disruption activates MAP kinase through phosphorylation.
Shinohara-Gotoh
Y
Y
Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.
Nishida
E
E
Hoshi
M
M
Sakai
H
H
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D003078:Colchicine / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D008870:Microtubules / Q000187:drug effects*; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats
D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D003078:Colchicine