Tissue transglutaminase directly regulates adenylyl cyclase resulting in enhanced cAMP-response element-binding protein (CREB) activation.
Tissue transglutaminase (tTG) is present in the human nervous system and is predominantly localized to neurons. Treatment of human neuroblastoma SH-SY5Y cells with retinoic acid results in increased tTG expression, which is both necessary and sufficient for differentiation. The goal of the present study was to determine whether tTG modulates the activation of the cyclic AMP-response element (CRE)-binding protein, CREB, an event that likely plays a central role in the differentiation of SH-SY5Y cells. SH-SY5Y cells stably transfected with active wild type tTG, tTG without transamidating activity (C277S), an antisense tTG construct that depleted the endogenous levels of tTG, or vector only were used for the study. Treatment with forskolin, an adenylyl cyclase activator, increased that activation-associated phosphorylation of CREB, which was prolonged by tTG overexpression. CRE-reporter gene activity was also significantly elevated in the tTG cells compared with the other cells. The enhancement of CREB phosphorylation/activation in the tTG cells is likely due to the fact that tTG significantly potentiates cAMP production, and our findings indicate that tTG enhances adenylyl cyclase activity by modulating the conformation state of adenylyl cyclase. This is the first study to provide evidence of the mechanism by which tTG may contribute to neuronal differentiation.
Tucholski
Janusz
J
Department of Psychiatry, University of Alabama at Birmingham, Birmingham, Alabama 35294-0017, USA.
Johnson
Gail V W
GV
D000262:Adenylyl Cyclases / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D002772:Cholera Toxin / Q000633:toxicity; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism*; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D010766:Phosphorylation; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D011503:Transglutaminases / Q000235:genetics / Q000378:metabolism*
D017362:Cyclic AMP Response Element-Binding Protein; D011994:Recombinant Proteins; D005576:Colforsin; D002772:Cholera Toxin; D000242:Cyclic AMP; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D019205:GTP-Binding Protein alpha Subunits, Gs; D000262:Adenylyl Cyclases