Characterization of microtubule-associated protein 1-associated protein kinases from rat brain.
The microtubule-associated protein (MAP) 1 preparation, MAP1A and 1B, obtained from rat brain microtubules was associated with protein kinases that were insensitive to cAMP, cGMP, calcium, calcium/calmodulin and calcium/phosphatidylserine. The fractionation of highly purified MAP1 by phosphocellulose chromatography revealed that protein kinase activity to phosphorylate phosvitin was separated into three major peaks (MAP1 kinases A, B and C). MAP1 was recovered in the MAP1 kinase A fraction and phosphorylated by the contained kinase. MAP1 kinase A is a novel protein kinase that is remarkably activated by poly-L-lysine and poly-L-arginine, but very insensitive to heparin among the kinases. Photoaffinity labeling using [alpha-32P]8-azido ATP indicated that the 65 kDa polypeptide is identified as an ATP-binding protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the highly purified MAP1 and MAP1 kinase A fractions. MAP1 kinases B and C may be identified as casein kinase I- and II-like kinases. The present results show that MAP1 is associated with at least three kinases and provide an insight for understanding thoroughly the MAP1-mediated microtubule functions.
Fujii
T
T
Department of Imagination Science and Technology (Kansei Engineering), Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan.
Watanabe
M
M
Nakamura
A
A
D000818:Animals; D001921:Brain / Q000201:enzymology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000032:analysis*; D010766:Phosphorylation; D051381:Rats; D013379:Substrate Specificity
D017871:Calcium-Calmodulin-Dependent Protein Kinases