title: Activation of p21-activated protein kinase alpha (alpha PAK) by hyperosmotic shock in neonatal ventricular myocytes.
abstract: The p21-activated protein kinases (PAKs) may participate in signalling from Cdc42/Rac1 to the stress-regulated MAPKs (SAPKs/JNKs and p38-/HOG-1-related-MAPKs). We characterized the expression and regulation of alpha PAK in cultured ventricular myocytes. alpha PAK was specifically immunoprecipitated from myocyte extracts. High basal alpha PAK activity was detected in unstimulated myocytes. Its activity was increased rapidly (<30 s) by hyperosmotic shock in the presence of okadaic acid, and was maximal by 3 min (187 +/- 7% relative to unstimulated cells). Endothelin-1 and interleukin-1beta, which also activate SAPKs/JNKs, did not increase alpha PAK activity and presumably act through different PAK isoforms or other mechanisms.
authors.affiliation: Division of Cardiac Medicine, Imperial College School of Medicine at N.H.L.I., London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Clerk
authors.forename: P H
authors.initials: PH
authors.lastname: Sugden
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002478:Cells, Cultured; D004789:Enzyme Activation; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D009997:Osmotic Pressure; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D054462:p21-Activated Kinases
chemical_list: C515906:Pak1 protein, rat; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases