{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nJP‑45 is an integral sarcoplasmic reticulum protein predominantly expressed in skeletal muscle where it plays a key role in excitation–contraction coupling. It achieves this by interacting with the voltage‐dependent Ca²⁺ channel Ca(v)1.1 and the Ca²⁺ storage protein calsequestrin, with its expression profile—appearing in mid‐embryogenesis, peaking during early postnatal development, and declining with age—underscoring its importance in muscle function and contractility."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nA separate study identified the gene FAM46D, also known as TENT5D, as a novel cancer/testis antigen. Distinguished by its restricted expression in normal tissues and its aberrant, tumor‐associated expression, TENT5D elicits a detectable antibody response exclusively in cancer patients, suggesting that it may serve as a promising immunotherapeutic target."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nFurther investigations into muscle physiology have revealed that the interplay between JP‑45 and calsequestrin isoforms finely tunes the activity of Ca(v)1.1 channels. In mouse models lacking these proteins, altered calcium entry through enhanced channel activity compensates for diminished sarcoplasmic reticulum Ca²⁺ content, indicating that the JP‑45–calsequestrin complex normally acts as a negative regulator of excitation‐coupled calcium entry, thereby sustaining proper tetanic force development."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Ayuk A Anderson, Susan Treves, Donatella Biral, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The novel skeletal muscle sarcoplasmic reticulum JP-45 protein. Molecular cloning, tissue distribution, developmental expression, and interaction with alpha 1.1 subunit of the voltage-gated calcium channel."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M305016200"}], "href": "https://doi.org/10.1074/jbc.M305016200"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12871958"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12871958"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Osvaldo Delbono, Jinyu Xia, Susan Treves, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Loss of skeletal muscle strength by ablation of the sarcoplasmic reticulum protein JP45."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Proc Natl Acad Sci U S A (2007)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1073/pnas.0707389104"}], "href": "https://doi.org/10.1073/pnas.0707389104"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "18077436"}], "href": "https://pubmed.ncbi.nlm.nih.gov/18077436"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Fabiana Bettoni, Fernando Camargo Filho, Daniela M Grosso, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Identification of FAM46D as a novel cancer/testis antigen using EST data and serological analysis."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Genomics (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.ygeno.2009.06.001"}], "href": "https://doi.org/10.1016/j.ygeno.2009.06.001"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19540335"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19540335"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Barbara Mosca, Osvaldo Delbono, Maria Laura Messi, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Enhanced dihydropyridine receptor calcium channel activity restores muscle strength in JP45/CASQ1 double knockout mice."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Nat Commun (2013)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/ncomms2496"}], "href": "https://doi.org/10.1038/ncomms2496"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23443569"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23443569"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Barbara Mosca, Jan Eckhardt, Leda Bergamelli, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Role of the JP45-Calsequestrin Complex on Calcium Entry in Slow Twitch Skeletal Muscles."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2016)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M115.709071"}], "href": "https://doi.org/10.1074/jbc.M115.709071"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "27189940"}], "href": "https://pubmed.ncbi.nlm.nih.gov/27189940"}]}]}]}