{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nAlthough none of the provided abstracts explicitly mention MIR6076, together they offer insight into the roles of SPCA2 isoforms—a family of secretory pathway Ca²⁺‐ATPases—with functions that may intersect with regulatory networks in which microRNAs (such as MIR6076) could be involved. In the first study, SPCA2 was shown to interact unconventionally with the Ca²⁺ influx channel Orai1 in mouse lactating mammary epithelial cells."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": " This interaction is crucial for mediating store-independent Ca²⁺ entry (SICE), which supports robust basolateral Ca²⁺ influx necessary for milk secretion, and highlights that SPCA2 is required for the plasma membrane trafficking of Orai1.\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nThe second abstract describes a distinct, acinar cell–specific transcript of the Atp2c2 gene (encoding SPCA2) that is normally expressed in pancreatic acinar cells and other serous exocrine cells."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": " In Mist1 knockout mice, which lack the transcription factor MIST1 that normally regulates secretory cell gene expression, there is a dramatic loss of this Atp2c2 transcript and SPCA2 protein, correlating with abnormal Ca²⁺ signaling and exocytosis. These findings imply that transcriptional regulation of SPCA2 is vital for maintaining Ca²⁺ homeostasis in secretory tissues.\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn the third study, researchers identified a novel pancreas‐specific isoform termed SPCA2C, which is expressed from an alternative transcriptional start site within the Atp2c2 gene."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": " This isoform encodes a protein corresponding to the carboxy terminal region of SPCA2 and uniquely contributes to increasing cytosolic Ca²⁺ levels in pancreatic acinar cells. Moreover, the diminished expression of Atp2c2c observed early during experimental pancreatitis indicates its relevance in the broader adaptive response of acinar cells to regulate intracellular Ca²⁺, distinguishing its function from that of other Ca²⁺ ATPases.\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Brandie M Cross, Anniesha Hack, Timothy A Reinhardt, et al. "}, {"type": "b", "children": [{"type": "t", "text": "SPCA2 regulates Orai1 trafficking and store independent Ca2+ entry in a model of lactation."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "PLoS One (2013)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1371/journal.pone.0067348"}], "href": "https://doi.org/10.1371/journal.pone.0067348"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23840669"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23840669"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Victoria C Garside, Agnes S Kowalik, Charis L Johnson, et al. "}, {"type": "b", "children": [{"type": "t", "text": "MIST1 regulates the pancreatic acinar cell expression of Atp2c2, the gene encoding secretory pathway calcium ATPase 2."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Exp Cell Res (2010)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.yexcr.2010.06.014"}], "href": "https://doi.org/10.1016/j.yexcr.2010.06.014"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "20599950"}], "href": "https://pubmed.ncbi.nlm.nih.gov/20599950"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Melissa A Fenech, Caitlin M Sullivan, Lucimar T Ferreira, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Atp2c2 Is Transcribed From a Unique Transcriptional Start Site in Mouse Pancreatic Acinar Cells."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Cell Physiol (2016)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1002/jcp.25391"}], "href": "https://doi.org/10.1002/jcp.25391"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "27017909"}], "href": "https://pubmed.ncbi.nlm.nih.gov/27017909"}]}]}]}