Cytoskeletal-associated protein kinase and phosphatase activities from cerebral cortex of young rats.
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.
de Freitas
M S
MS
Departamento de Bioquimica, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS-Brasil.
de Mattos
A G
AG
Camargo
M M
MM
Wannmacher
C
C
Pessoa-Pureur
R
R
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002540:Cerebral Cortex / Q000201:enzymology* / Q000648:ultrastructure; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003599:Cytoskeleton / Q000201:enzymology*; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D011092:Polyethylene Glycols; D051381:Rats; D017208:Rats, Wistar; D012995:Solubility
D011092:Polyethylene Glycols; D017868:Cyclic AMP-Dependent Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D010749:Phosphoprotein Phosphatases