TI - Alleviating the suppression of glycogen synthase kinase -3beta by Akt leads to the phosphorylation of cAMP-response element -binding protein and its transactivation in intact cell nuclei . AB - Glycogen synthase kinase-3beta ( GSK-3beta ) activity is suppressed when it becomes phosphorylated on serine 9 by protein kinase B (Akt) . To determine how GSK-3beta activity opposes Akt function we used various methods to alleviate GSK-3beta suppression in prostate carcinoma cells . In some experiments , LY294002 , a specific inhibitor of phosphatidylinositol 3-kinase ( a kinase involved in activating Akt ) and tumor necrosis factor-alpha ( TNF-alpha ) were used to activate GSK-3beta . In other experiments mutant forms of GSK-3beta , GSK-3betadelta9 ( a constitutively active deletion mutant of GSK-3beta ) and GSK-3betaY216F ( an inactive point mutant of GSK-3beta ) were used to alter GSK-3beta activity . LY294002 , TNF-alpha , and overexpression of wild-type GSK-3beta or of GSK-3betadelta9 , but not GSK-3betaY216F , alleviated the suppression of GSK-3beta activity in prostate carcinoma cells and enhanced the turnover of beta-catenin . Forced expression of wild-type GSK-3beta or of GSK-3betadelta9 , but not GSK-3betaY216F , suppressed cell growth and showed that the phosphorylation status of GSK-3beta can affect its intracellular distribution . When transcription factors activator protein-1 and cyclic AMP-response element ( CRE )- binding protein were analyzed as targets of GSK-3beta activity , overexpression of wild-type GSK-3beta suppressed AP1 -mediated transcription and activated CRE -mediated transcription . Overexpression of GSK-3betadelta9 caused an ( 80-fold ) increase in CRE -mediated transcription , which was further amplified ( up to 130-fold ) by combining GSK-3betadelta9 overexpression with the suppression of Jun activity . This study also demonstrated for the first time that expression of constitutively active GSK-3betadelta9 results in the phosphorylation of CRE -binding protein on serine 129 and enhancement of CRE -mediated transcription in intact cell nuclei .