Anti-GSK-3α/β (Tyr-279/Tyr-216), Phosphospecific Antibody

Glycogen synthase kinase-3 (GSK-3) has been implicated in fundamental cell processes such as cell fate determination, metabolism, transcriptional control, and oncogenesis. Two GSK-3 genes (α and β) have been cloned in mammals and these kinase homologues show strong sequence conservation within their catalytic domain. GSK-3β plays a critical role in cell survival by phosphorylating nuclear factor-κB (NF-κB) p65 subunit, leading to NF-κB transactivation in hepatocytes. Phosphorylation regulates the activity of both GSK-3 genes. MEK1/2 can phosphorylate tyrosine 216 (tyrosine 279 in GSK-3α), which stimulates GSK-3 kinase activity. Tyr-216 phosphorylation is required for GSK-mediated down-regulation of β-catenin activity. Also, TRAIL stimulation can increase Tyr-216 phosphorylation, and GSK-3β activity may suppress TRAIL-induced apoptosis. Inactiviation of GSK-3 occurs through Akt phosphorylation of serine 9 of GSK-3β (Serine 21 in GSK-3α). This phosphorylation may be involved in later phases of neuronal apoptosis.