RT Journal Article SR Electronic T1 Role of Protein Kinase Cα in Signaling from the Histamine H1 Receptor to the Nucleus JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 1012 OP 1021 DO 10.1124/mol.59.5.1012 VO 59 IS 5 A1 A. C. Megson A1 E. M. Walker A1 S. J. Hill YR 2001 UL http://molpharm.aspetjournals.org/content/59/5/1012.abstract AB Stimulation of histamine H1 receptors produced a marked activation of inositol phospholipid hydrolysis, intracellular calcium mobilization, and stimulation of the c-fos promoter in CHO-H1 cells expressing the H1 receptor at a level of 3 pmol/mg protein. The latter response was determined using a luciferase-based reporter gene (pGL3). This response to histamine was not sensitive to inhibition by pertussis toxin but could be completely attenuated by the protein kinase C (PKC) inhibitor Ro-31-8220, or by 24-h pretreatment with the phorbol esters phorbol 12,13-dibutyrate or phorbol-12-myristate-13-acetate. Several isoforms of PKC can be detected in CHO-H1 cells (α, δ, ε, μ, ι, ζ) but only PKCα and PKCδ were down-regulated by prolonged treatment with phorbol esters. Of the two isoforms that were down-regulated, only protein kinase Cα was translocated to CHO-H1 cell membranes after stimulation with either histamine or phorbol esters. The PKC inhibitor Gö6976, which inhibits PKCα but not PKCδ, was also able to significantly attenuate the c-fos-luciferase response to histamine. The mitogen-activated protein kinase kinase inhibitor PD 98059 markedly inhibited the response to histamine, suggesting that the likely major target for PKCα was the mitogen-activated protein kinase pathway. These data suggest that the histamine H1 receptor can signal to the nucleus via PKCα after activation of phospholipase Cβ.