TI - Glycogen synthase kinase -3beta : homologous regulation of cell surface insulin receptor level via controlling insulin receptor mRNA stability in adrenal chromaffin cells . AB - In cultured bovine adrenal chromaffin cells , 48 h-treatment with 20 mmol/L LiCl , 1 mmol/L valproic acid , 30 micromol/L SB216763 , 30 micromol/L SB415286 , or 100 nmol/L insulin , a condition that inhibits constitutive active glycogen synthase kinase-3 ( GSK-3 ) , decreased cell surface ( 125 ) I-insulin binding capacity by approximately 39% , without altering the K(d) value ; LiCl , SB216763 or insulin decreased insulin receptor ( IR ) and IR precursor levels , attenuating insulin-induced Tyr-autophosphorylation of IR . LiCl increased inhibitory Ser9-phosphorylation of GSK-3beta at 6 h , decreasing ( 125 ) I-insulin binding at 24 h . SB216763 -induced ( 125 ) I-insulin binding reduction ( IC ( 50 ) = 3 micromol/L ) was preceded by beta-catenin level increase by SB216763 ( EC ( 50 ) = 11 micromol/L ) , a hallmark of GSK-3 inhibition . Insulin-induced rapid ( &gt ; 1 min ) Ser9-phosphorylation of GSK-3beta ( Nemoto et al. 2006 ) was followed by approximately 48% decrease of IR level . LiCl did not stimulate endocytosis , nor proteolysis of IR . LiCl destabilized IR mRNA ( t ( 1/2 ) = 9.3 vs. 6.5 h ) , decreasing IR mRNA level by approximately 47% , without altering IR gene transcription . Decreases of ( 125 ) I-insulin binding and IR level , as well as increased Ser9-phosphorylation of GSK-3beta were restored to the control levels by washing the test compound -treated cells . Thus , GSK-3beta regulates IR level via controlling IR mRNA stability .