Regulation of the human atrial myosin light chain 1 promoter by Ca2+-calmodulin-dependent signaling pathways.
We investigated expression regulation of the human atrial myosin light chain 1 (hALC-1) gene using a cardiomyocyte H9c2 cell line stably transfected with a construct consisting of the human ALC-1 promoter cloned in front of the luciferase gene (H9c2T1). H9c2T1 cells were stimulated with vasopressin, which is known to induce cardiomyocyte hypertrophy and to activate a panel of signaling pathways. Those pathways involved in hALC-1 promoter activity regulation were dissected by using pharmacological inhibitor substances. Stimulation with vasopressin was associated with nuclear NFAT translocation and significantly increased human ALC-1 promoter activity. Inhibition of calcineurin by cyclosporin A blocked the effects of vasopressin on ALC-1 promoter activity to approximately 50%. This suggests that the Ca2+-calmodulin-calcineurin-NFAT pathway is involved in human ALC-1 promoter activation. However, inhibition of multifunctional Ca2+-calmodulin-dependent protein kinases (CaMK) by KN-93 decreased human ALC-1 promoter activity to almost basal levels. CaMK regulation of ALC-1 promoter activity effect could well be mediated by CaMKIV, which accumulated in the nucleus upon vasopressin stimulation. Inhibition of protein kinase C (PKC) isoforms by bisindolylmaleimide had no significant influence on human ALC-1 promoter activity. Thus, our results demonstrate a dominant role of Ca2+-calmodulin-dependent signaling pathways in the regulation of human ALC-1 expression.
Woischwill
Christiane
C
Max-Delbrück-Center for Molecular Medicine, Berlin-Buch, Germany.
Karczewski
Peter
P
Bartsch
Holger
H
Luther
Hans-Peter
HP
Kott
Monika
M
Haase
Hannelore
H
Morano
Ingo
I
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000032:analysis / Q000378:metabolism; D002147:Calmodulin / Q000494:pharmacology*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004622:Embryo, Mammalian; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects*; D005838:Genotype; D006321:Heart; D006801:Humans; D015151:Immunoblotting; D007527:Isoenzymes / Q000032:analysis; D008156:Luciferases / Q000235:genetics; D032383:Myocytes, Cardiac; D018994:Myosin Light Chains / Q000235:genetics*; D050778:NFATC Transcription Factors / Q000032:analysis / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D051381:Rats; D011993:Recombinant Fusion Proteins; D014162:Transfection; D014667:Vasopressins / Q000494:pharmacology
D002147:Calmodulin; D007527:Isoenzymes; D018994:Myosin Light Chains; D050778:NFATC Transcription Factors; D011993:Recombinant Fusion Proteins; C491915:hALC-1 protein, human; D014667:Vasopressins; D008156:Luciferases; D011493:Protein Kinase C; C517683:CAMK4 protein, human; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C517686:Camk4 protein, rat; D002118:Calcium