{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nRecent studies on the Usher protein network have established that the scaffold protein SANS (the USH1G gene product) is central to the integrity and function of the mechanotransduction apparatus in auditory hair cells. In particular, SANS localizes predominantly at the tips of short- and middle‐row stereocilia, where it interacts with tip‐link components cadherin‑23 and protocadherin‑15 to maintain stereocilia cohesion and shape. These features profoundly affect both the amplitude and sensitivity of the transducer currents, and disruptions here are linked to deficits in actin polymerization and stereocilia length regulation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nGenetic analyses using various mouse models have further demonstrated that mutations in USH1G/SANS lead to disorganized stereocilia bundles and, in some cases, congenital profound deafness. Digenic heterozygous combinations involving USH1G and other key USH proteins—for example, MYO7A, CDH23, and PCDH15—result in accelerated stereocilia degeneration and progressive hearing loss. Moreover, the absence of harmonin (USH1C) causes mis‐localization of both SANS and protocadherin‑15, underscoring the interdependence of these scaffolding components for proper complex assembly and hair bundle maintenance."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "3", "end_ref": "5"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn addition to its role in auditory function, the USH protein network also regulates retinal photoreceptor homeostasis. Here, SANS participates in distinct complexes—one of which involves an interaction with Magi2—to mediate receptor‐dependent, clathrin‐mediated endocytosis. This process is essential for proper ciliogenesis at the photoreceptor’s periciliary membrane complex and provides a potential mechanistic link to oxidative stress–induced cone degeneration seen in certain Usher syndrome models. Structural insights into related scaffolding proteins such as whirlin further emphasize the importance of dynamic protein–protein interactions in sensory cell function. Such multifaceted roles for scaffold proteins suggest that regulatory factors like MIR3179‑4—although not directly characterized in these studies—may be critical modulators of USH network expression and assembly, fine‐tuning both hair bundle mechanotransduction and photoreceptor maintenance."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "6", "end_ref": "8"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Elisa Caberlotto, Vincent Michel, Isabelle Foucher, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Usher type 1G protein sans is a critical component of the tip-link complex, a structure controlling actin polymerization in stereocilia."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Proc Natl Acad Sci U S A (2011)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1073/pnas.1017114108"}], "href": "https://doi.org/10.1073/pnas.1017114108"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21436032"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21436032"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Yoshiaki Kikkawa, Hiroshi Shitara, Shigeharu Wakana, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Mutations in a new scaffold protein Sans cause deafness in Jackson shaker mice."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Hum Mol Genet (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1093/hmg/ddg042"}], "href": "https://doi.org/10.1093/hmg/ddg042"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12588793"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12588793"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Qing Yin Zheng, John D Scarborough, Ye Zheng, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Digenic inheritance of deafness caused by 8J allele of myosin-VIIA and mutations in other Usher I genes."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Hum Mol Genet (2012)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1093/hmg/dds084"}], "href": "https://doi.org/10.1093/hmg/dds084"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "22381527"}], "href": "https://pubmed.ncbi.nlm.nih.gov/22381527"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Yuki Miyasaka, Hiroshi Shitara, Sari Suzuki, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Heterozygous mutation of Ush1g/Sans in mice causes early-onset progressive hearing loss, which is recovered by reconstituting the strain-specific mutation in Cdh23."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Hum Mol Genet (2016)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1093/hmg/ddw078"}], "href": "https://doi.org/10.1093/hmg/ddw078"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "26936824"}], "href": "https://pubmed.ncbi.nlm.nih.gov/26936824"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Denise Yan, Kazusaku Kamiya, Xiao Mei Ouyang, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Analysis of subcellular localization of Myo7a, Pcdh15 and Sans in Ush1c knockout mice."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Int J Exp Pathol (2011)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1111/j.1365-2613.2010.00751.x"}], "href": "https://doi.org/10.1111/j.1365-2613.2010.00751.x"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21156003"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21156003"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Alix Trouillet, Elisabeth Dubus, Julie Dégardin, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Cone degeneration is triggered by the absence of USH1 proteins but prevented by antioxidant treatments."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Sci Rep (2018)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/s41598-018-20171-0"}], "href": "https://doi.org/10.1038/s41598-018-20171-0"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "29386551"}], "href": "https://pubmed.ncbi.nlm.nih.gov/29386551"}]}, {"type": "r", "ref": 7, "children": [{"type": "t", "text": "Katharina Bauß, Barbara Knapp, Pia Jores, et al. 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