3pvl

Structural highlights

Disease

[Q5MJ57_MOUSE] Defects in Myo7a are the cause of the shaker-1 (sh-1) phenotype which affects only the inner ear. Sh-1 homozygote mutants show hyperactivity, head tossing and circling due to vestibular dysfunction, together with typical neuroepithelial-type cochlear defects involving dysfunction and progressive degeneration of the organ of Corti.^[1] [USH1G_HUMAN] Defects in USH1G are the cause of Usher syndrome type 1G (USH1G) [MIM:606943]. USH is a genetically heterogeneous condition characterized by the association of retinitis pigmentosa and sensorineural deafness. Age at onset and differences in auditory and vestibular function distinguish Usher syndrome type 1 (USH1), Usher syndrome type 2 (USH2) and Usher syndrome type 3 (USH3). USH1 is characterized by profound congenital sensorineural deafness, absent vestibular function and prepubertal onset of progressive retinitis pigmentosa leading to blindness.^{[2] [3] [4] [5]}

Function

[Q5MJ57_MOUSE] Myosins are actin-based motor molecules with ATPase activity. Unconventional myosins serve in intracellular movements. Their highly divergent tails bind to membranous compartments, which are then moved relative to actin filaments. In the retina, plays an important role in the renewal of the outer photoreceptor disks. Plays an important role in the distribution and migration of retinal pigment epithelial (RPE) melanosomes and phagosomes, and in the regulation of opsin transport in retinal photoreceptors. Mediates intracellular transport of RPE65 in the retina pigment epithelium. In the inner ear, plays an important role in differentiation, morphogenesis and organization of cochlear hair cell bundles. Motor protein that is a part of the functional network formed by USH1C, USH1G, CDH23 and MYO7A that mediates mechanotransduction in cochlear hair cells. Required for normal hearing. Involved in hair-cell vesicle trafficking of aminoglycosides, which are known to induce ototoxicity.^{[6] [7]} [USH1G_HUMAN] Required for normal development and maintenance of cochlear hair cell bundles. Anchoring/scaffolding protein that is a part of the functional network formed by USH1C, USH1G, CDH23 and MYO7A that mediates mechanotransduction in cochlear hair cells. Required for normal hearing.^{[8] [9]}

See Also

• Myosin

References

1. ↑ Gibson F, Walsh J, Mburu P, Varela A, Brown KA, Antonio M, Beisel KW, Steel KP, Brown SD. A type VII myosin encoded by the mouse deafness gene shaker-1. Nature. 1995 Mar 2;374(6517):62-4. PMID:7870172 doi:http://dx.doi.org/10.1038/374062a0
2. ↑ Grati M, Kachar B. Myosin VIIa and sans localization at stereocilia upper tip-link density implicates these Usher syndrome proteins in mechanotransduction. Proc Natl Acad Sci U S A. 2011 Jul 12;108(28):11476-81. doi:, 10.1073/pnas.1104161108. Epub 2011 Jun 27. PMID:21709241 doi:10.1073/pnas.1104161108
3. ↑ Weil D, El-Amraoui A, Masmoudi S, Mustapha M, Kikkawa Y, Laine S, Delmaghani S, Adato A, Nadifi S, Zina ZB, Hamel C, Gal A, Ayadi H, Yonekawa H, Petit C. Usher syndrome type I G (USH1G) is caused by mutations in the gene encoding SANS, a protein that associates with the USH1C protein, harmonin. Hum Mol Genet. 2003 Mar 1;12(5):463-71. PMID:12588794
4. ↑ Yan J, Pan L, Chen X, Wu L, Zhang M. The structure of the harmonin/sans complex reveals an unexpected interaction mode of the two Usher syndrome proteins. Proc Natl Acad Sci U S A. 2010 Feb 8. PMID:20142502
5. ↑ Kalay E, de Brouwer AP, Caylan R, Nabuurs SB, Wollnik B, Karaguzel A, Heister JG, Erdol H, Cremers FP, Cremers CW, Brunner HG, Kremer H. A novel D458V mutation in the SANS PDZ binding motif causes atypical Usher syndrome. J Mol Med (Berl). 2005 Dec;83(12):1025-32. Epub 2005 Nov 8. PMID:16283141 doi:10.1007/s00109-005-0719-4
6. ↑ Lopes VS, Gibbs D, Libby RT, Aleman TS, Welch DL, Lillo C, Jacobson SG, Radu RA, Steel KP, Williams DS. The Usher 1B protein, MYO7A, is required for normal localization and function of the visual retinoid cycle enzyme, RPE65. Hum Mol Genet. 2011 Jul 1;20(13):2560-70. doi: 10.1093/hmg/ddr155. Epub 2011 Apr , 14. PMID:21493626 doi:http://dx.doi.org/10.1093/hmg/ddr155
7. ↑ Grati M, Kachar B. Myosin VIIa and sans localization at stereocilia upper tip-link density implicates these Usher syndrome proteins in mechanotransduction. Proc Natl Acad Sci U S A. 2011 Jul 12;108(28):11476-81. doi:, 10.1073/pnas.1104161108. Epub 2011 Jun 27. PMID:21709241 doi:10.1073/pnas.1104161108
8. ↑ Grati M, Kachar B. Myosin VIIa and sans localization at stereocilia upper tip-link density implicates these Usher syndrome proteins in mechanotransduction. Proc Natl Acad Sci U S A. 2011 Jul 12;108(28):11476-81. doi:, 10.1073/pnas.1104161108. Epub 2011 Jun 27. PMID:21709241 doi:10.1073/pnas.1104161108
9. ↑ Weil D, El-Amraoui A, Masmoudi S, Mustapha M, Kikkawa Y, Laine S, Delmaghani S, Adato A, Nadifi S, Zina ZB, Hamel C, Gal A, Ayadi H, Yonekawa H, Petit C. Usher syndrome type I G (USH1G) is caused by mutations in the gene encoding SANS, a protein that associates with the USH1C protein, harmonin. Hum Mol Genet. 2003 Mar 1;12(5):463-71. PMID:12588794
10. ↑ Wu L, Pan L, Wei Z, Zhang M. Structure of MyTH4-FERM domains in myosin VIIa tail bound to cargo. Science. 2011 Feb 11;331(6018):757-60. PMID:21311020 doi:10.1126/science.1198848