Glycogen Synthase Kinase 3 Beta (GSK3b)

Glycogen synthase kinase-3 (GSK3) is a proline-directed serine-threonine kinase that was initially identified as a phosphorylating and inactivating glycogen synthase. Two isoforms, alpha (GSK3A) and beta, show a high degree of amino acid homology. GSK3B is involved in energy metabolism, neuronal cell development, and body pattern formation (Plyte et al., 1992). By Northern blot analysis, Lau et al. (1999) showed that GSK3B is predominantly expressed as 8.3- and 2.8-kb transcripts in testis, thymus, prostate, and ovary, but weakly expressed in lung and kidney. Western blot analysis revealed expression of a 46-kD protein in lung, kidney, and brain. By comparative analysis of various promoter constructs, Lau et al. (1999) observed that GSK3B expression is greater in neuronal than in kidney cell lines.