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.

Clone M132 was generated from a phospho-GSK-3β (Tyr-216) synthetic peptide (coupled to KLH) corresponding to amino acid residues around tyrosine 216 of human GSK-3β.

The antibody detects 46/50 kDa* proteins corresponding to the apparent molecular mass of GSK-3β and GSK-3α on SDS-PAGE immunoblots of pervanadate treated rabbit fibroblasts, as well as treated human SKN-SH and A431 cells. This peptide sequence is also found in GSK-3α (Tyr-279) and is highly conserved in GSK-3 genes in rat and mouse.