title: NFAT1 and NFAT3 cooperate with HDAC4 during regulation of alternative splicing of PMCA isoforms in PC12 cells.
abstract: BACKGROUND
  The bulk of human genes undergo alternative splicing (AS) upon response to physiological stimuli. AS is a great source of protein diversity and biological processes and is associated with the development of many diseases. Pheochromocytoma is a neuroendocrine tumor, characterized by an excessive Ca2+-dependent secretion of catecholamines. This underlines the importance of balanced control of calcium transport via regulation of gene expression pattern, including different calcium transport systems, such as plasma membrane Ca2+-ATPases (PMCAs), abundantly expressed in pheochromocytoma chromaffin cells (PC12 cells). PMCAs are encoded by four genes (Atp2b1, Atp2b2, Atp2b3, Atp2b4), whose transcript products undergo alternative splicing giving almost 30 variants.
  
  
  RESULTS
  In this scientific report, we propose a novel mechanism of regulation of PMCA alternative splicing in PC12 cells through cooperation of the nuclear factor of activated T-cells (NFAT) and histone deacetylases (HDACs). Luciferase assays showed increased activity of NFAT in PC12 cells, which was associated with altered expression of PMCA. RT-PCR experiments suggested that inhibition of the transcriptional activity of NFAT might result in the rearrangement of PMCA splicing variants in PC12 cells. NFAT inhibition led to dominant expression of 2x/c, 3x/a and 4x/a PMCA variants, while in untreated cells the 2w,z/b, 3z,x/b,c,e,f, and 4x/b variants were found as well. Furthermore, chromatin immunoprecipitation experiments showed that NFAT1-HDAC4 or NFAT3-HDAC4 complexes might be involved in regulation of PMCA2x splicing variant generation.
  
  
  CONCLUSIONS
  We suggest that the influence of NFAT/HDAC on PMCA isoform composition might be important for altered dopamine secretion by PC12 cells.
authors.affiliation: Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland; Department of Neurodegenerative Disorders, Laboratory of Neurogenetics, Mossakowski Medical Research Centre PAS, Warsaw, Poland.
authors.forename: Michalina
authors.initials: M
authors.lastname: Kosiorek
authors.affiliation: Laboratory of Cytometry, Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: Paulina
authors.initials: P
authors.lastname: Podszywalow-Bartnicka
authors.affiliation: Department of Molecular Neurochemistry, Medical University, Lodz, Poland.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Zylinska
authors.affiliation: Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: Slawomir
authors.initials: S
authors.lastname: Pikula
mesh_terms: D017398:Alternative Splicing / Q000502:physiology*; D000818:Animals; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016716:PC12 Cells; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats
chemical_list: D007527:Isoenzymes; D050778:NFATC Transcription Factors; C559944:HDAC4 protein, rat; D006655:Histone Deacetylases; D053499:Plasma Membrane Calcium-Transporting ATPases