Phosphorylated mitogen-activated protein kinase/extracellular signal-regulated kinase 1/2 may not always represent its kinase activity in a rat model of focal cerebral ischemia with or without ischemic preconditioning

• Published in: Neuroscience 2012-05, Vol.209, p.155-160
• Main Authors: Takahashi, T, Steinberg, G.K, Zhao, H
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Blotting, Western; Brain Ischemia - enzymology; Disease Models, Animal; Enzyme Activation - physiology; ERK1/2; focal ischemia; Fundamental and applied biological sciences. Psychology; Ischemic Preconditioning; kinase activity; Male; MAPK; Medical sciences; Mitogen-Activated Protein Kinase 1 - analysis; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3 - analysis; Mitogen-Activated Protein Kinase 3 - metabolism; Neurology; Phosphorylation; Rats; Rats, Sprague-Dawley; stroke; Vascular diseases and vascular malformations of the nervous system; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2012.02.005

Abstract The extracellular signal-regulated kinase (ERK) 1/2 protein requires a dual phosphorylation at conserved threonine and tyrosine residues to be fully activated under normal physiological conditions. Thus, ERK1/2 kinase activity is often defined by the quantity of phosphorylated kinase. However, this may not accurately represent its true activity under certain pathological conditions. We investigated whether ERK1/2 kinase activity is proportional to its phosphorylation state in a rat focal ischemia model with and without rapid ischemic preconditioning. We showed that phosphorylated-ERK1/2 protein levels were increased 2.6±0.07-fold, and ERK1/2 kinase activity was increased 10.6±1.9-fold in animals receiving ischemic preconditioning alone without test ischemia compared with sham group ( P