Description
Two GSK-3 genes (alpha and beta) have been cloned in mammals and these kinase homologues show strong sequence conservation within their catalytic domain. GSK-3beta plays a critical role in cell survival by phosphorylating nuclear factor-kappaB (NF-kappaB) p65 subunit, leading to NF-kappaB transactivation in hepatocytes. Phosphorylation regulates the activity of both GSK-3 genes. MEK1/2 can phosphorylate tyrosine 216 (tyrosine 279 in GSK-3alpha), which stimulates GSK-3 kinase activity. Tyr-216 phosphorylation is required for GSK-mediated down-regulation of beta-catenin activity. Also, TRAIL stimulation can increase Tyr-216 phosphorylation, and GSK-3beta activity may suppress TRAIL-induced apoptosis. Inactiviation of GSK-3 occurs through Akt phosphorylation of serine 9 of GSK-3beta (Serine 21 in GSK-3alpha). This phosphorylation may be involved in later phases of neuronal apoptosis.Human recombinant GSK-3beta protein is a 20kDa fragment that includes amino acids 2 to 159. This GSK-3beta protein fragment is detected by mouse monoclonal anti-GSK-3beta (N-terminal region)