title: Transient receptor potential melastatin-3 (TRPM3)-induced activation of AP-1 requires Ca2+ ions and the transcription factors c-Jun, ATF2, and ternary complex factor.
abstract: The steroid pregnenolone sulfate activates the transcription factor activator protein-1 (AP-1) via stimulation of transient receptor potential melastatin-3 (TRPM3) channels. Here, we show that the signaling pathway requires an influx of Ca(2+) ions into the cells and a rise in the intracellular Ca(2+) levels. The upregulation of AP-1 was attenuated in cells that overexpressed mitogen activated protein kinase phosphatase-1, indicating that Ca(2+) ions prolong the signaling cascade via activation of mitogen activated protein kinases. On the transcriptional level, expression of a dominant-negative mutant of the basic region leucine zipper protein c-Jun, a major constituent of the AP-1 transcription factor complex, or expression of a c-Jun-specific short hairpin RNA attenuated pregnenolone sulfate-induced AP-1 activation. In addition, stimulation of TRPM3 channels increased the transcriptional activation potential of the basic region leucine zipper protein ATF2. Inhibition of ATF2 target gene expression via expression of a dominant-negative mutant of ATF2 or expression of an ATF2-specific short hairpin RNA interfered with TRPM3-mediated stimulation of AP-1. Moreover, we show that a dominant-negative mutant of the ternary complex factor (TCF) Elk-1 attenuated the upregulation of AP-1 following stimulation of TRPM3 channels. Thus, c-Jun, ATF2, and TCFs are required to connect the intracellular signaling cascade elicited by activation of TRPM3 channels with enhanced transcription of AP-1-regulated genes. We conclude that pregnenolone sulfate-induced TRPM3 channel activation changes the gene expression pattern of the cells by activating transcription of c-Jun-, ATF2-, and TCF-controlled genes.
authors.affiliation: Department of Medical Biochemistry and Molecular Biology (A.L., G.T.) and Department of Anatomy and Cell Biology, University of Saarland Medical Faculty, Homburg, Germany (X.H., P.L.).
authors.forename: Andrea
authors.initials: A
authors.lastname: Lesch
authors.affiliation: Department of Medical Biochemistry and Molecular Biology (A.L., G.T.) and Department of Anatomy and Cell Biology, University of Saarland Medical Faculty, Homburg, Germany (X.H., P.L.).
authors.forename: Xin
authors.initials: X
authors.lastname: Hui
authors.affiliation: Department of Medical Biochemistry and Molecular Biology (A.L., G.T.) and Department of Anatomy and Cell Biology, University of Saarland Medical Faculty, Homburg, Germany (X.H., P.L.).
authors.forename: Peter
authors.initials: P
authors.lastname: Lipp
authors.affiliation: Department of Medical Biochemistry and Molecular Biology (A.L., G.T.) and Department of Anatomy and Cell Biology, University of Saarland Medical Faculty, Homburg, Germany (X.H., P.L.) gerald.thiel@uks.eu.
authors.forename: Gerald
authors.initials: G
authors.lastname: Thiel
mesh_terms: D051698:Activating Transcription Factor 2 / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002412:Cations; D057809:HEK293 Cells; D006801:Humans; D011284:Pregnenolone / Q000494:pharmacology; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000378:metabolism*; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*; D050801:Ternary Complex Factors / Q000235:genetics / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014158:Transcription, Genetic; D015854:Up-Regulation; D050807:ets-Domain Protein Elk-1 / Q000235:genetics / Q000378:metabolism
chemical_list: D051698:Activating Transcription Factor 2; D002412:Cations; D016755:Proto-Oncogene Proteins c-jun; D050053:TRPM Cation Channels; C475667:TRPM3 protein, human; D050801:Ternary Complex Factors; D018808:Transcription Factor AP-1; D050807:ets-Domain Protein Elk-1; C018370:pregnenolone sulfate; D011284:Pregnenolone; D002118:Calcium