{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nSTARD7 is an intracellular lipid transfer protein that plays a pivotal role in mediating phosphatidylcholine (PC) delivery to mitochondria. It exists in distinct isoforms that differ in their targeting and subcellular distribution—for example, an N‐terminal mitochondrial‐targeted form (StarD7‑I) and a cytosolic variant (StarD7‑II)—and it harbors a C‑terminal START domain that binds PC as well as ceramide. In vitro studies demonstrate that STARD7 catalyzes PC transfer between membranes, and its processing by mitochondrial proteases regulates its partitioning between the mitochondrial intermembrane space and the cytosol, thereby influencing mitochondrial membrane composition and cristae architecture."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "5"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nThe proper function of STARD7 is essential for mitochondrial homeostasis, as its activity is linked to maintaining mitochondrial PC levels, preserving abnormal mitochondrial morphology, and ensuring optimal respiratory function. Reduced expression or functional impairment of STARD7 leads to mitochondrial and endoplasmic reticulum stress responses, altered reactive oxygen species homeostasis, and compromised cellular differentiation processes such as myogenesis and trophoblast development."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}, {"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its core lipid transfer functions, STARD7 expression is tightly regulated by key signaling pathways including Wnt/β‑catenin and by transcription factors such as SF‑1 and TCF4, underscoring its broader role in cellular lipid metabolism. In addition, genetic abnormalities—for instance, intronic ATTTC repeat expansions in the STARD7 gene—have been linked to disorders like familial adult myoclonic epilepsy, while altered STARD7 expression has been reported in various cancers, including lung cancer, suggesting potential diagnostic and prognostic implications. Intriguingly, STARD7 also exhibits fusogenic properties at lipid–membrane interfaces, a function that may contribute to membrane remodeling events."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "8", "end_ref": "13"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Yasuhiro Horibata, Hiroyuki Sugimoto "}, {"type": "b", "children": [{"type": "t", "text": "StarD7 mediates the intracellular trafficking of phosphatidylcholine to mitochondria."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2010)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M109.056960"}], "href": "https://doi.org/10.1074/jbc.M109.056960"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "20042613"}], "href": "https://pubmed.ncbi.nlm.nih.gov/20042613"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Yasuhiro Horibata, Hiromi Ando, Motoyasu Satou, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Identification of the N-terminal transmembrane domain of StarD7 and its importance for mitochondrial outer membrane localization and phosphatidylcholine transfer."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Sci Rep (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/s41598-017-09205-1"}], "href": "https://doi.org/10.1038/s41598-017-09205-1"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "28821867"}], "href": "https://pubmed.ncbi.nlm.nih.gov/28821867"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Shotaro Saita, Takashi Tatsuta, Philipp A Lampe, et al. 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