Role of PKC¦Á?p³⁸MAPK?G_i¦Á axis in peroxynitrite-mediated inhibition of ¦Â-adrenergic response in pulmonary artery smooth muscle cells

详细信息    查看全文

• 作者：Sajal Chakraborti^a ; ^{sajal_chakraborti@yahoo.com} ; Soumitra Roy^a ; Animesh Chowdhury^a ; Amritlal Mandal^b ; Tapati Chakraborti^a
• 关键词：ONOO&minus ; peroxynitrite ; PKC-¦Á ; protein kinase C-¦Á ; p38MAPK ; p38mitogen activated protein kinase ; cAMP ; cyclic adenosine monophosphate ; Gi¦Á ; alpha subunit of Gi ; CZI ; myristoylated PKC-¦Æ pseudosubstrate peptide (myr-RRGARRWRK) inhibitor ; CEI ; myris
• 刊名：Cellular Signalling
• 出版年：2013
• 出版时间：February, 2013
• 年：2013
• 卷：25
• 期：2
• 页码：512-526
• 全文大小：1882 K

文摘

In the context of cross-talk between transmembrane signaling pathways, we studied the loci within the ¦Â-adrenergic receptor/G protein/adenyl cyclase system at which PKC exerts regulatory effects of peroxynitrite (ONOO^?) on isoproterenol stimulated adenyl cyclase activity in pulmonary artery smooth muscle cells. Treatment of the cells with ONOO^? stimulated PKC-¦Á activity and that subsequently increased p³⁸MAPK phosphorylation. Pretreatment with Go6976 (PKC-¦Á inhibitor) and SB203580 (p³⁸MAPK inhibitor) eliminated ONOO^? caused inhibition on isoproterenol stimulated adenyl cyclase activity. Pretreatment with Go6976, but not SB203580, prevented ONOO^? induced increase in PKC-¦Á activity. Studies using genetic inhibitors of PKC-¦Á (PKC-¦Á siRNA) and p³⁸MAPK (p³⁸MAPK siRNA) also corroborated the findings obtained with their pharmacological inhibitors in eliminating the attenuation of ONOO^? effect on isoproterenol stimulated adenyl cyclase activity. This inhibitory effect of ONOO^? was found to be eliminated upon pretreatment of the cells with pertussis toxin thereby pointing to a G_i dependent mechanism. This hypothesis was reinforced by G_i¦Á phosphorylation as well as by the observation of the loss of the ability of Gpp(NH)p (a measure of G_i mediated response) to stimulate adenyl cyclase activity upon ONOO^? treatment to the cells. We suggest the existence of a pertussis toxin sensitive G protein (G_i)-mediated mechanism in isoproterenol stimulated adenyl cyclase activity, which is regulated by PKC¦Á-p³⁸MAPK axis dependent phosphorylation of its ¦Á-subunit (G_i¦Á) in the pulmonary artery smooth muscle cells.