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Protein kinase A and protein kinase C signaling pathway interaction in phenylethanolamine N ‐methyltransferase gene regulation
Author(s) -
Tai T. C.,
Wong Dona L.
Publication year - 2003
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2003.01728.x
Subject(s) - forskolin , protein kinase c , protein kinase a , microbiology and biotechnology , phenylethanolamine n methyltransferase , phenylethanolamine , promoter , biology , signal transduction , transcription factor , reporter gene , creb , chemistry , kinase , stimulation , gene , gene expression , biochemistry , endocrinology , enzyme , tyrosine hydroxylase
Abstract The protein kinase A (PKA) and protein kinase C (PKC) signaling pathways appear to interact in regulating phenylethanolamine N ‐methyltransferase (PNMT) promoter‐driven gene transcription in PC12 cells. Forskolin treatment of cells transfected with the rat PNMT promoter‐luciferase reporter gene construct pGL3RP893 increased promoter activity approximately two‐fold whereas phorbol‐12‐myristate‐13 acetate (PMA) treatment had no effect. However, simultaneous forskolin and PMA treatment synergistically activated the PNMT promoter approximately four‐fold, suggesting that PKC stimulation requires prior induction of the PKA pathway. Consistent with this possibility the adenylate cyclase inhibitor MDL12,330A, and the PKA inhibitor H‐89 prevented PNMT promoter stimulation by the combination of forskolin and PMA. PKA and PKC regulation seems to be mediated in part by Egr‐1 and Sp1 through their consensus elements in the PNMT promoter. Forskolin and PMA treatment of PC12 cells increased Egr‐1 protein and phosphorylated Egr‐1/DNA‐binding complex formation to the same extent but only increased phosphorylated Sp1/DNA binding complex formation without altering Sp1 protein levels. Mutation of the − 165 bp Egr‐1 and − 48 bp Sp1 sites, respectively, attenuated and abolished combined forskolin and PMA‐mediated promoter activation. PNMT promoter analysis further showed that synergistic stimulation by PKA and PKC involves DNA sequences between − 442 and − 392 bp, and potentially a GCM binding element lying within this region.