- 作者: Boris Tabakoff Eric Nelson Masami Yoshimura Kaisa Hellevuo Paula L. Hoffman
- 作者服務機構: Department of Pharmacology, University of Colorado Health Sciences Center, Denver, Colo., USA
- 中文摘要: --
- 英文摘要: Our studies indicate that, in the presence of particularisoforms of adenylyl cyclase (i.e., type 7 AC), moderatelyintoxicating concentrations of ethanol will significantlypotentiate transmitter-mediated activation of the cAMPsignaling cascade. Activation of this signaling cascademay have important implications for the mechanisms bywhich ethanol produces intoxication, and/or for themechanisms of neuroadaptation leading to tolerance to,and physical dependence on, ethanol. We initiated aseries of studies to investigate the phosphorylation ofAC7 by PKC, the role of this phosphorylation in modulat-ing the sensitivity of AC7 to activation by Gsα, and thePKC isotype(s) involved in the phosphorylation of AC7.The T7 epitope-tagged AC7 expressed in Sf9 and HEK293cells was found to be phosphorylated in vitro by the cata-lytic subunit of PKC. Treatment of AC7-transfectedHEK293 cells with phorbol dibutyrate (PDBu) or ethanolincreased the phosphorylation of AC7 and its respon-siveness to Gsα. In human erythroleukemia (HEL) cells,which endogeneously express AC7, ethanol and PDBuincreased AC activity stimulated by PGE . The potentia-tion by both PDBu and ethanol was found to be sensitiveto the PKC -selective inhibitor, rottlerin. The potentia-tion of AC activity by ethanol in HEL cells was also selec-tively attenuated by the RACK inhibitory peptide specificfor PKC , and by expression of the dominant negative,catalytically inactive, form of PKC . These data demon-strate that AC7 can be phosphorylated by PKC, leading toan increase in functional activity, and ethanol can poten-tiate AC7 activity through a PKC -mediated phosphory-lation of AC7.
- 中文關鍵字: --
- 英文關鍵字: Alcohol. adenylyl cyclase. cAMP. Protein kinase A. Protein kinase C