Cytoskeletal-associated protein kinase and phosphatase activities from cerebral cortex of young rats

• Published in: Neurochemical research 1995-08, Vol.20 (8), p.951-956
• Main Authors: DE FREITAS, M. S, DE MATTOS, A. G, CAMARGO, M. M, WANNMACHER, C. M. D, PESSOA-PUREUR, R
• Format: Article
• Language: English
• Subjects: Animals; Biochemistry and metabolism; Biological and medical sciences; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Central nervous system; Cerebral Cortex - enzymology; Cerebral Cortex - ultrastructure; Cyclic AMP-Dependent Protein Kinases - metabolism; Cytoskeleton - enzymology; Fundamental and applied biological sciences. Psychology; Phosphoprotein Phosphatases - metabolism; Polyethylene Glycols; Rats; Rats, Wistar; Solubility; Vertebrates: nervous system and sense organs
• ISSN: 0364-3190; 1573-6903
• DOI: 10.1007/BF00970741

We describe the phosphorylation system associated with the Triton-insoluble cytoskeletal fraction that phosphorylates in vitro the 150 kDa neurofilament subunit (NF-M) and alpha and beta tubulin from cerebral cortex of rats. The protein kinase activities were determined in the presence of 20 microM cyclic AMP (cAMP), 1 mM calcium and 1 microM calmodulin (Ca2+/calmodulin) or 1 mM calcium, 0.2 mM phosphatidylserine and 0.5 microM phorbol 12,13-dibutyrate (Ca2+/PS/PDBu). Phosphorylation of these cytoskeletal proteins increased approximately 35% and 65% in the presence of cAMP and Ca2+/calmodulin, respectively, but was unaffected in the presence of Ca2+/PS/PDBu. Basal phosphorylation of these proteins studied increased approximately 35% and 72% in the presence of 0.5 microM okadaic acid and 0.01 microM microcystin-LR, respectively, suggesting the presence of phosphatase type 1. Results suggest that at least two protein kinases and one protein phosphatase are associated with the Triton-insoluble cytoskeletal fraction from cerebral cortex of rats.