title: Atp2c2 Is Transcribed From a Unique Transcriptional Start Site in Mouse Pancreatic Acinar Cells.
abstract: Proper regulation of cytosolic Ca(2+) is critical for pancreatic acinar cell function. Disruptions in normal Ca(2+) concentrations affect numerous cellular functions and are associated with pancreatitis. Membrane pumps and channels regulate cytosolic Ca(2+) homeostasis by promoting rapid Ca(2+) movement. Determining how expression of Ca(2+) modulators is regulated and the cellular alterations that occur upon changes in expression can provide insight into initiating events of pancreatitis. The goal of this study was to delineate the gene structure and regulation of a novel pancreas-specific isoform for Secretory Pathway Ca(2+) ATPase 2 (termed SPCA2C), which is encoded from the Atp2c2 gene. Using Next Generation Sequencing of RNA (RNA-seq), chromatin immunoprecipitation for epigenetic modifications and promoter-reporter assays, a novel transcriptional start site was identified that promotes expression of a transcript containing the last four exons of the Atp2c2 gene (Atp2c2c). This region was enriched for epigenetic marks and pancreatic transcription factors that promote gene activation. Promoter activity for regions upstream of the ATG codon in Atp2c2's 24th exon was observed in vitro but not in in vivo. Translation from this ATG encodes a protein aligned with the carboxy terminal of SPCA2. Functional analysis in HEK 293A cells indicates a unique role for SPCA2C in increasing cytosolic Ca(2+) . RNA analysis indicates that the decreased Atp2c2c expression observed early in experimental pancreatitis reflects a global molecular response of acinar cells to reduce cytosolic Ca(2+) levels. Combined, these results suggest SPCA2C affects Ca(2+) homeostasis in pancreatic acinar cells in a unique fashion relative to other Ca(2+) ATPases. J. Cell. Physiol. 231: 2768-2778, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Children's Health Research Institute, London, Ontario, Canada.|Department of Pediatrics, University of Western Ontario, London, Ontario, Canada.|Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Fenech
authors.affiliation: Children's Health Research Institute, London, Ontario, Canada.|Department of Pediatrics, University of Western Ontario, London, Ontario, Canada.|Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.
authors.forename: Caitlin M
authors.initials: CM
authors.lastname: Sullivan
authors.affiliation: Children's Health Research Institute, London, Ontario, Canada.|Department of Pediatrics, University of Western Ontario, London, Ontario, Canada.
authors.forename: Lucimar T
authors.initials: LT
authors.lastname: Ferreira
authors.affiliation: Children's Health Research Institute, London, Ontario, Canada.|Department of Pediatrics, University of Western Ontario, London, Ontario, Canada.
authors.forename: Rashid
authors.initials: R
authors.lastname: Mehmood
authors.affiliation: Magee-Womens Research Institute and Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: William A
authors.initials: WA
authors.lastname: MacDonald
authors.affiliation: Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Stathopulos
authors.affiliation: Children's Health Research Institute, London, Ontario, Canada.|Department of Pediatrics, University of Western Ontario, London, Ontario, Canada.|Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.|Department of Oncology, University of Western Ontario, London, Ontario, Canada.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Pin
mesh_terms: D061354:Acinar Cells / Q000378:metabolism* / Q000473:pathology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002108:Ceruletide; D044127:Epigenesis, Genetic; D005091:Exons / Q000235:genetics; D005260:Female; D016678:Genome; D057809:HEK293 Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D008297:Male; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010179:Pancreas / Q000473:pathology*; D010195:Pancreatitis / Q000235:genetics / Q000473:pathology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
chemical_list: D006657:Histones; D012333:RNA, Messenger; C528285:SPCA2 protein, mouse; D002108:Ceruletide; D000252:Calcium-Transporting ATPases; D002118:Calcium