Ets and GATA Transcription Factors Play a Critical Role in PMA-Mediated Repression of the ck beta Promoter via the Protein Kinase C Signaling Pathway: e113485

• Published in: PloS one 2014-12, Vol.9 (12)
• Main Authors: Kuan, Chee Sian, Yee, Yoke Hiang, Too, Wei CunSee, Few, Ling Ling
• Format: Article
• Language: English
• ISSN: 1932-6203
• DOI: 10.1371/journal.pone.0113485

Background Choline kinase is the most upstream enzyme in the CDP-choline pathway. It catalyzes the phosphorylation of choline to phosphorylcholine in the presence of ATP and Mg2+ during the biosynthesis of phosphatidylcholine, the major phospholipid in eukaryotic cell membranes. In humans, choline kinase (CK) is encoded by two separate genes, ck alpha and ck beta , which produce three isoforms, CK alpha 1, CK alpha 2, and CK beta . Previous studies have associated ck beta with muscle development; however, the molecular mechanism underlying the transcriptional regulation of ck beta has never been elucidated. Methodology/Principal Findings In this report, the distal promoter region of the ck beta gene was characterized. Mutational analysis of the promoter sequence and electrophoretic mobility shift assays (EMSA) showed that Ets and GATA transcription factors were essential for the repression of ck beta promoter activity. Supershift and chromatin immunoprecipitation (ChIP) assays further identified that GATA3 but not GATA2 was bound to the GATA site of ck beta promoter. In addition, phorbol-12-myristate-13-acetate (PMA) decreased ck beta promoter activity through Ets and GATA elements. PMA also decreased the ck beta mRNA and protein levels about 12 hours after the promoter activity was down-regulated. EMSA further revealed that PMA treatment increased the binding of both Ets and GATA transcription factors to their respective DNA elements. The PMA-mediated repressive effect was abolished by chronic PMA treatment and by treatment with the PKC inhibitor PKC412, but not the PKC inhibitor Go 6983, suggesting PKC epsilon or PKC eta as the PKC isozyme involved in the PMA-mediated repression of ck beta promoter. Further confirmation by using PKC isozyme specific inhibitors identified PKC epsilon as the isozyme that mediated the PMA repression of ck beta promoter. Conclusion/Significance These results demonstrate the participation of the PKC signaling pathway in the regulation of ck beta gene transcription by Ets and GATA transcription factors.