 Abnormal regulation and expression of GSK3β is associated with an increased susceptibility towards bipolar disorder.Glycogen synthase kinase-3 (GSK-3) is a proline-directed serine-threonine kinase that was initially identified as a phosphorylating and an inactivating agent of glycogen synthase.Two isoforms, alpha (GSK3A) and beta, show a high degree of amino acid homology.