5un2
Crystal Structure of Mouse Cadherin-23 EC19-21 with non-syndromic deafness (DFNB12) associated mutation R2029W
Structural highlights
DiseaseCAD23_MOUSE Defects in Cdh23 are the cause of waltzer (v) phenotype. Waltzer mice are characterized by deafness and vestibular dysfunction due to degeneration of the neuroepithelium within the inner ear. FunctionCAD23_MOUSE Cadherins are calcium-dependent cell adhesion proteins. They preferentially interact with themselves in a homophilic manner in connecting cells. CDH23 is required for establishing and/or maintaining the proper organization of the stereocilia bundle of hair cells in the cochlea and the vestibule during late embryonic/early postnatal development. It is part of the functional network formed by USH1C, USH1G, CDH23 and MYO7A that mediates mechanotransduction in cochlear hair cells. Required for normal hearing.[1] Publication Abstract from PubMedCadherin-23 (CDH23) is an essential component of hair-cell tip links, fine filaments that mediate inner-ear mechanotransduction. The extracellular domain of CDH23 forms about three-fourths of the tip link with 27 extracellular cadherin (EC) repeats that are structurally similar but not identical to each other. Calcium (Ca(2+)) coordination at the EC linker regions is key for tip-link elasticity and function. There are approximately 116 sites in CDH23 affected by deafness-causing mutations, many of which alter conserved Ca(2+)-binding residues. Here we present crystal structures showing 18 CDH23 EC repeats, including the most and least conserved, a fragment carrying disease mutations, and EC repeats with non-canonical Ca(2+)-binding motif sequences and unusual secondary structure. Complementary experiments show deafness mutations' effects on stability and affinity for Ca(2+). Additionally, a model of nine contiguous CDH23 EC repeats reveals helicity and potential parallel dimerization faces. Overall, our studies provide detailed structural insight into CDH23 function in mechanotransduction. Zooming in on Cadherin-23: Structural Diversity and Potential Mechanisms of Inherited Deafness.,Jaiganesh A, De-la-Torre P, Patel AA, Termine DJ, Velez-Cortes F, Chen C, Sotomayor M Structure. 2018 Jun 27. pii: S0969-2126(18)30209-0. doi:, 10.1016/j.str.2018.06.003. PMID:30033219[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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