Up-regulation of TRPM6 transcriptional activity by AP-1 in renal epithelial cells.
Transient receptor potential melastatin 6 (TRPM6) channel is involved in the reabsorption of magnesium in the kidney. We recently found that TRPM6 expression is up-regulated by EGF, but the regulatory mechanism has not been clear. TRPM6 mRNA was endogenously expressed in HEK293 cells. TRPM6 mRNA expression was increased by EGF, which was inhibited by U0126, an MEK inhibitor. Promoter activity of human TRPM6 was observed in the TRPM6 5'-flanking region from -1,214 to -718. This promoter activity was enhanced by EGF and inhibited by U0126. Three putative AP-1 binding sites were identified within the region of -1,214/-718. The mutation of the putative AP-1 binding site (-741/-736) completely inhibited the EGF-induced promoter activity. EGF increased p-ERK1/2, c-Fos, c-Jun, and p-c-Jun levels, which were inhibited by U0126. The introduction of c-Fos or c-Jun siRNA inhibited the EGF-induced promoter activity. A chromatin immunoprecipitation assay revealed that c-Fos and c-Jun bind to the AP-1 binding site within the region of -1,214/-718. These results suggest that EGF up-regulates TRPM6 mRNA expression mediate via the activation of ERK/AP-1-dependent pathway.
Ikari
Akira
A
Department of Pharmaco-Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Shizuoka, Japan. ikari@u-shizuoka-ken.ac.jp
Sanada
Ayumi
A
Okude
Chiaki
C
Sawada
Hayato
H
Yamazaki
Yasuhiro
Y
Sugatani
Junko
J
Miwa
Masao
M
D024506:5' Flanking Region; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002070:Butadienes / Q000494:pharmacology; D002460:Cell Line; D004815:Epidermal Growth Factor / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects; D014162:Transfection; D015854:Up-Regulation
D002070:Butadienes; D009570:Nitriles; D047428:Protein Kinase Inhibitors; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D050053:TRPM Cation Channels; C459082:TRPM6 protein, human; C507531:TRPM6 protein, rat; D018808:Transcription Factor AP-1; C113580:U 0126; D004815:Epidermal Growth Factor; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020930:MAP Kinase Kinase Kinases