1
|
Pedro De-la-Torre, Wen H, Brower J, Martínez-Pérez K, Narui Y, Yeh F, Hale E, Ivanchenko MV, Corey DP, Sotomayor M, Indzhykulian AA. Elasticity and Thermal Stability are Key Determinants of Hearing Rescue by Mini-Protocadherin-15 Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.16.599132. [PMID: 38948700 PMCID: PMC11212938 DOI: 10.1101/2024.06.16.599132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Protocadherin-15 is a core protein component of inner-ear hair-cell tip links pulling on transduction channels essential for hearing and balance. Protocadherin-15 defects can result in non-syndromic deafness or Usher syndrome type 1F (USH1F) with hearing loss, balance deficits, and progressive blindness. Three rationally engineered shortened versions of protocadherin-15 (mini-PCDH15s) amenable for gene therapy have been used to rescue function in USH1F mouse models. Two can successfully or partially rescue hearing, while another one fails. Here we show that despite varying levels of hearing rescue, all three mini-PCDH15 versions can rescue hair-cell mechanotransduction. Negative-stain electron microscopy shows that all three versions form dimers like the wild-type protein, while crystal structures of some engineered fragments show that these can properly fold and bind calcium ions essential for function. In contrast, simulations predict distinct elasticities and nano differential scanning fluorimetry shows differences in melting temperature measurements. Our data suggest that elasticity and thermal stability are key determinants of sustained hearing rescue by mini-PCDH15s.
Collapse
Affiliation(s)
- Pedro De-la-Torre
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
| | - Haosheng Wen
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
- Biophysics Program, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
| | - Joseph Brower
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
| | - Karina Martínez-Pérez
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
- Biology Program, Department of Basic Sciences, Universidad del Atlántico, Cra 30 # 8-49, Puerto Colombia, 081007, Colombia
| | - Yoshie Narui
- Center for Electron Microscopy and Analysis, The Ohio State University, 1275-1305 Kinnear Road, Columbus, OH, USA
| | - Frank Yeh
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
| | - Evan Hale
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
- Speech and Hearing Biosciences and Technology graduate program, Harvard University, Cambridge, MA, USA
| | - Maryna V. Ivanchenko
- Department of Neurobiology, Harvard Medical School, 200 Longwood Ave, Boston, MA, USA
| | - David P. Corey
- Department of Neurobiology, Harvard Medical School, 200 Longwood Ave, Boston, MA, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
- Biophysics Program, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
| | - Artur A. Indzhykulian
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
- Speech and Hearing Biosciences and Technology graduate program, Harvard University, Cambridge, MA, USA
| |
Collapse
|
2
|
Tamilselvan E, Sotomayor M. CELSR1, a core planar cell polarity protein, features a weakly adhesive and flexible cadherin ectodomain. Structure 2024; 32:476-491.e5. [PMID: 38307021 DOI: 10.1016/j.str.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 09/30/2023] [Accepted: 01/08/2024] [Indexed: 02/04/2024]
Abstract
Planar cell polarity (PCP), essential to multicellular developmental processes, arises when cells polarize and align across tissues. Central to PCP is CELSR1, an atypical cadherin featuring a long ectodomain with nine extracellular cadherin (EC) repeats, a membrane adjacent domain (MAD10), and several characteristic adhesion GPCR domains. Cell-based aggregation assays have demonstrated CELSR1's homophilic adhesive nature, but mechanistic details are missing. Here, we investigate the possible adhesive properties and structures of CELSR1 EC repeats. Our bead aggregation assays do not support strong adhesion by EC repeats alone. Consistently, EC1-4 only dimerizes at high concentration in solution. Crystal structures of human CELSR1 EC1-4 and EC4-7 reveal typical folds and a non-canonical linker between EC5 and EC6. Simulations and experiments using EC4-7 indicate flexibility at EC5-6, and solution experiments show EC7-MAD10-mediated dimerization. Our results suggest weak homophilic adhesion by CELSR1 cadherin repeats and provide mechanistic insights into the structural determinants of CELSR1 function.
Collapse
Affiliation(s)
- Elakkiya Tamilselvan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Biophysics Program, The Ohio State University, Columbus, OH 43210, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Biophysics Program, The Ohio State University, Columbus, OH 43210, USA.
| |
Collapse
|
3
|
Arora N, Hazra JP, Roy S, Bhati GK, Gupta S, Yogendran KP, Chaudhuri A, Sagar A, Rakshit S. Emergence of slip-ideal-slip behavior in tip-links serve as force filters of sound in hearing. Nat Commun 2024; 15:1595. [PMID: 38383683 PMCID: PMC10881517 DOI: 10.1038/s41467-024-45423-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 01/23/2024] [Indexed: 02/23/2024] Open
Abstract
Tip-links in the inner ear convey force from sound and trigger mechanotransduction. Here, we present evidence that tip-links (collectively as heterotetrameric complexes of cadherins) function as force filters during mechanotransduction. Our force-clamp experiments reveal that the tip-link complexes show slip-ideal-slip bond dynamics. At low forces, the lifetime of the tip-link complex drops monotonically, indicating slip-bond dynamics. The ideal bond, rare in nature, is seen in an intermediate force regime where the survival of the complex remains constant over a wide range. At large forces, tip-links follow a slip bond and dissociate entirely to cut-off force transmission. In contrast, the individual tip-links (heterodimers) display slip-catch-slip bonds to the applied forces. While with a phenotypic mutant, we showed the importance of the slip-catch-slip bonds in uninterrupted hearing, our coarse-grained Langevin dynamics simulations demonstrated that the slip-ideal-slip bonds emerge as a collective feature from the slip-catch-slip bonds of individual tip-links.
Collapse
Affiliation(s)
- Nisha Arora
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Jagadish P Hazra
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Sandip Roy
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Gaurav K Bhati
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Sarika Gupta
- National Institute of Immunology, New Delhi, India
| | - K P Yogendran
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Abhishek Chaudhuri
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India.
| | - Amin Sagar
- Centre de Biologie Structurale, INSERM, CNRS, Université de Montpellier, Montpellier, France.
| | - Sabyasachi Rakshit
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India.
| |
Collapse
|
4
|
Ivanchenko MV, Hathaway DM, Klein AJ, Pan B, Strelkova O, De-la-Torre P, Wu X, Peters CW, Mulhall EM, Booth KT, Goldstein C, Brower J, Sotomayor M, Indzhykulian AA, Corey DP. Mini-PCDH15 gene therapy rescues hearing in a mouse model of Usher syndrome type 1F. Nat Commun 2023; 14:2400. [PMID: 37100771 PMCID: PMC10133396 DOI: 10.1038/s41467-023-38038-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 04/11/2023] [Indexed: 04/28/2023] Open
Abstract
Usher syndrome type 1 F (USH1F), caused by mutations in the protocadherin-15 gene (PCDH15), is characterized by congenital deafness, lack of balance, and progressive blindness. In hair cells, the receptor cells of the inner ear, PCDH15 is a component of tip links, fine filaments which pull open mechanosensory transduction channels. A simple gene addition therapy for USH1F is challenging because the PCDH15 coding sequence is too large for adeno-associated virus (AAV) vectors. We use rational, structure-based design to engineer mini-PCDH15s in which 3-5 of the 11 extracellular cadherin repeats are deleted, but which still bind a partner protein. Some mini-PCDH15s can fit in an AAV. An AAV encoding one of these, injected into the inner ears of mouse models of USH1F, produces a mini-PCDH15 which properly forms tip links, prevents the degeneration of hair cell bundles, and rescues hearing. Mini-PCDH15s may be a useful therapy for the deafness of USH1F.
Collapse
Affiliation(s)
| | - Daniel M Hathaway
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Alex J Klein
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Bifeng Pan
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Olga Strelkova
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Pedro De-la-Torre
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Xudong Wu
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Cole W Peters
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Eric M Mulhall
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Kevin T Booth
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Corey Goldstein
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Joseph Brower
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Artur A Indzhykulian
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - David P Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
5
|
Qiu X, Müller U. Sensing sound: Cellular specializations and molecular force sensors. Neuron 2022; 110:3667-3687. [PMID: 36223766 PMCID: PMC9671866 DOI: 10.1016/j.neuron.2022.09.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/03/2022] [Accepted: 09/14/2022] [Indexed: 11/08/2022]
Abstract
Organisms of all phyla express mechanosensitive ion channels with a wide range of physiological functions. In recent years, several classes of mechanically gated ion channels have been identified. Some of these ion channels are intrinsically mechanosensitive. Others depend on accessory proteins to regulate their response to mechanical force. The mechanotransduction machinery of cochlear hair cells provides a particularly striking example of a complex force-sensing machine. This molecular ensemble is embedded into a specialized cellular compartment that is crucial for its function. Notably, mechanotransduction channels of cochlear hair cells are not only critical for auditory perception. They also shape their cellular environment and regulate the development of auditory circuitry. Here, we summarize recent discoveries that have shed light on the composition of the mechanotransduction machinery of cochlear hair cells and how this machinery contributes to the development and function of the auditory system.
Collapse
Affiliation(s)
- Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| |
Collapse
|
6
|
Elferich J, Clark S, Ge J, Goehring A, Matsui A, Gouaux E. Molecular structures and conformations of protocadherin-15 and its complexes on stereocilia elucidated by cryo-electron tomography. eLife 2021; 10:74512. [PMID: 34964715 PMCID: PMC8776254 DOI: 10.7554/elife.74512] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/27/2021] [Indexed: 11/23/2022] Open
Abstract
Mechanosensory transduction (MT), the conversion of mechanical stimuli into electrical signals, underpins hearing and balance and is carried out within hair cells in the inner ear. Hair cells harbor actin-filled stereocilia, arranged in rows of descending heights, where the tips of stereocilia are connected to their taller neighbors by a filament composed of protocadherin 15 (PCDH15) and cadherin 23 (CDH23), deemed the ‘tip link.’ Tension exerted on the tip link opens an ion channel at the tip of the shorter stereocilia, thus converting mechanical force into an electrical signal. While biochemical and structural studies have provided insights into the molecular composition and structure of isolated portions of the tip link, the architecture, location, and conformational states of intact tip links, on stereocilia, remains unknown. Here, we report in situ cryo-electron microscopy imaging of the tip link in mouse stereocilia. We observe individual PCDH15 molecules at the tip and shaft of stereocilia and determine their stoichiometry, conformational heterogeneity, and their complexes with other filamentous proteins, perhaps including CDH23. The PCDH15 complexes occur in clusters, frequently with more than one copy of PCDH15 at the tip of stereocilia, suggesting that tip links might consist of more than one copy of PCDH15 complexes and, by extension, might include multiple MT complexes.
Collapse
Affiliation(s)
- Johannes Elferich
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Sarah Clark
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Jingpeng Ge
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - April Goehring
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Aya Matsui
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Eric Gouaux
- Vollum Institute, Oregon Health and Science University, Portland, United States
| |
Collapse
|
7
|
Gray ME, Johnson ZR, Modak D, Tamilselvan E, Tyska MJ, Sotomayor M. Heterophilic and homophilic cadherin interactions in intestinal intermicrovillar links are species dependent. PLoS Biol 2021; 19:e3001463. [PMID: 34871294 PMCID: PMC8691648 DOI: 10.1371/journal.pbio.3001463] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/21/2021] [Accepted: 10/30/2021] [Indexed: 11/19/2022] Open
Abstract
Enterocytes are specialized epithelial cells lining the luminal surface of the small intestine that build densely packed arrays of microvilli known as brush borders. These microvilli drive nutrient absorption and are arranged in a hexagonal pattern maintained by intermicrovillar links formed by 2 nonclassical members of the cadherin superfamily of calcium-dependent cell adhesion proteins: protocadherin-24 (PCDH24, also known as CDHR2) and the mucin-like protocadherin (CDHR5). The extracellular domains of these proteins are involved in heterophilic and homophilic interactions important for intermicrovillar function, yet the structural determinants of these interactions remain unresolved. Here, we present X-ray crystal structures of the PCDH24 and CDHR5 extracellular tips and analyze their species-specific features relevant for adhesive interactions. In parallel, we use binding assays to identify the PCDH24 and CDHR5 domains involved in both heterophilic and homophilic adhesion for human and mouse proteins. Our results suggest that homophilic and heterophilic interactions involving PCDH24 and CDHR5 are species dependent with unique and distinct minimal adhesive units.
Collapse
Affiliation(s)
- Michelle E. Gray
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, United States of America
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Zachary R. Johnson
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Debadrita Modak
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Elakkiya Tamilselvan
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
- Biophysics Program, The Ohio State University, Columbus, Ohio, United States of America
| | - Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Marcos Sotomayor
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, United States of America
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
- Biophysics Program, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
| |
Collapse
|
8
|
Nishiguchi S, Oda H. Structural variability and dynamics in the ectodomain of an ancestral-type classical cadherin revealed by AFM imaging. J Cell Sci 2021; 134:269231. [PMID: 34152409 PMCID: PMC8325961 DOI: 10.1242/jcs.258388] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/15/2021] [Indexed: 01/13/2023] Open
Abstract
Type III cadherin represents the ancestral form of classical cadherin in bilaterian metazoans. Drosophila possesses type III and type IVa cadherins, known as DN- and DE-cadherins, respectively. Mature DN- and DE-cadherins have 15 and 7 extracellular cadherin domain (EC) repeats, respectively, with DN-cadherin EC6–EC11 homologous to DE-cadherin EC1–EC6. These EC repeats contain predicted complete or partial Ca2+-free inter-EC linkers that potentially contribute to adhesion. Comparative structure–function studies of DN- and DE-cadherins may help us understand the ancestral and derived states of classical cadherin-mediated adhesion mechanisms. Here, using bead aggregation assays, we found that DN-cadherin EC1–EC11 and DE-cadherin EC1–EC6 exhibit Ca2+-dependent adhesive properties. Using high-speed atomic force microscopy (HS-AFM) imaging in solution, we show that both DN- and DE-cadherin ectodomains share a common morphological framework consisting of a strand-like and a globule-like portion. Furthermore, the DN-cadherin EC repeats are highly variable, flexible in morphology and have at least three bendable sites, one of which is located in EC6–EC11 and can act as a flexible hinge. Our findings provide insights into diversification of classical cadherin-mediated adhesion mechanisms. This article has an associated First Person interview with the first author of the paper. Summary: Atomic force microscopy imaging reveals that the ectodomain of an ancestral-type classical cadherin has a flexibly bendable strand-like portion responsible for homophilic adhesion.
Collapse
Affiliation(s)
- Shigetaka Nishiguchi
- Laboratory of Evolutionary Cell and Developmental Biology, JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan.,Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.,R&D Group, Olympus Corporation, 2-3 Kuboyama-cho, Hachioji-shi, Tokyo 192-8512, Japan
| | - Hiroki Oda
- Laboratory of Evolutionary Cell and Developmental Biology, JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka 569-1125, Japan.,Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| |
Collapse
|
9
|
Fuster-García C, García-Bohórquez B, Rodríguez-Muñoz A, Aller E, Jaijo T, Millán JM, García-García G. Usher Syndrome: Genetics of a Human Ciliopathy. Int J Mol Sci 2021; 22:6723. [PMID: 34201633 PMCID: PMC8268283 DOI: 10.3390/ijms22136723] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/21/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive syndromic ciliopathy characterized by sensorineural hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. There are three clinical types depending on the severity and age of onset of the symptoms; in addition, ten genes are reported to be causative of USH, and six more related to the disease. These genes encode proteins of a diverse nature, which interact and form a dynamic protein network called the "Usher interactome". In the organ of Corti, the USH proteins are essential for the correct development and maintenance of the structure and cohesion of the stereocilia. In the retina, the USH protein network is principally located in the periciliary region of the photoreceptors, and plays an important role in the maintenance of the periciliary structure and the trafficking of molecules between the inner and the outer segments of photoreceptors. Even though some genes are clearly involved in the syndrome, others are controversial. Moreover, expression of some USH genes has been detected in other tissues, which could explain their involvement in additional mild comorbidities. In this paper, we review the genetics of Usher syndrome and the spectrum of mutations in USH genes. The aim is to identify possible mutation associations with the disease and provide an updated genotype-phenotype correlation.
Collapse
Affiliation(s)
- Carla Fuster-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Belén García-Bohórquez
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Ana Rodríguez-Muñoz
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Elena Aller
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Teresa Jaijo
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - José M. Millán
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Gema García-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| |
Collapse
|
10
|
Whatley M, Francis A, Ng ZY, Khoh XE, Atlas MD, Dilley RJ, Wong EYM. Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy. Front Genet 2020; 11:565216. [PMID: 33193648 PMCID: PMC7642844 DOI: 10.3389/fgene.2020.565216] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive (AR) disorder that permanently and severely affects the senses of hearing, vision, and balance. Three clinically distinct types of USH have been identified, decreasing in severity from Type 1 to 3, with symptoms of sensorineural hearing loss (SNHL), retinitis pigmentosa (RP), and vestibular dysfunction. There are currently nine confirmed and two suspected USH-causative genes, and a further three candidate loci have been mapped. The proteins encoded by these genes form complexes that play critical roles in the development and maintenance of cellular structures within the inner ear and retina, which have minimal capacity for repair or regeneration. In the cochlea, stereocilia are located on the apical surface of inner ear hair cells (HC) and are responsible for transducing mechanical stimuli from sound pressure waves into chemical signals. These signals are then detected by the auditory nerve fibers, transmitted to the brain and interpreted as sound. Disease-causing mutations in USH genes can destabilize the tip links that bind the stereocilia to each other, and cause defects in protein trafficking and stereocilia bundle morphology, thereby inhibiting mechanosensory transduction. This review summarizes the current knowledge on Usher syndrome with a particular emphasis on mutations in USH genes, USH protein structures, and functional analyses in animal models. Currently, there is no cure for USH. However, the genetic therapies that are rapidly developing will benefit from this compilation of detailed genetic information to identify the most effective strategies for restoring functional USH proteins.
Collapse
Affiliation(s)
- Meg Whatley
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Abbie Francis
- Ear Science Institute Australia, Nedlands, WA, Australia
- Emergency Medicine, The University of Western Australia, Nedlands, WA, Australia
| | - Zi Ying Ng
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Xin Ee Khoh
- Ear Science Institute Australia, Nedlands, WA, Australia
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Marcus D. Atlas
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
| | - Rodney J. Dilley
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- Centre for Cell Therapy and Regenerative Medicine, The University of Western Australia, Perth, WA, Australia
| | - Elaine Y. M. Wong
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
| |
Collapse
|
11
|
Structural determinants of protocadherin-15 mechanics and function in hearing and balance perception. Proc Natl Acad Sci U S A 2020; 117:24837-24848. [PMID: 32963095 PMCID: PMC7547225 DOI: 10.1073/pnas.1920444117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
When sound vibrations reach the inner ear, fine protein filaments called “tip links” stretch and open cochlear hair-cell mechanosensitive channels that trigger sensory perception. Similarly, vestibular hair cells use tip links to sense mechanical stimuli produced by head motions. Tip links are formed by cadherin-23 and protocadherin-15, two large proteins involved in hearing loss and balance disorders. Here we present multiple structures, models, and simulations that depict the lower end of the tip link, including the complete protocadherin-15 ectodomain. These models show an essential connection between cadherin-23 and protocadherin-15 with dual molecular “handshakes” and various protein sites that are mutated in inherited deafness. The simulations also reveal how the tip link responds to force to mediate hearing and balance sensing. The vertebrate inner ear, responsible for hearing and balance, is able to sense minute mechanical stimuli originating from an extraordinarily broad range of sound frequencies and intensities or from head movements. Integral to these processes is the tip-link protein complex, which conveys force to open the inner-ear transduction channels that mediate sensory perception. Protocadherin-15 and cadherin-23, two atypically large cadherins with 11 and 27 extracellular cadherin (EC) repeats, are involved in deafness and balance disorders and assemble as parallel homodimers that interact to form the tip link. Here we report the X-ray crystal structure of a protocadherin-15 + cadherin-23 heterotetrameric complex at 2.9-Å resolution, depicting a parallel homodimer of protocadherin-15 EC1-3 molecules forming an antiparallel complex with two cadherin-23 EC1-2 molecules. In addition, we report structures for 10 protocadherin-15 fragments used to build complete high-resolution models of the monomeric protocadherin-15 ectodomain. Molecular dynamics simulations and validated crystal contacts are used to propose models for the complete extracellular protocadherin-15 parallel homodimer and the tip-link bond. Steered molecular dynamics simulations of these models suggest conditions in which a structurally diverse and multimodal protocadherin-15 ectodomain can act as a stiff or soft gating spring. These results reveal the structural determinants of tip-link–mediated inner-ear sensory perception and elucidate protocadherin-15’s structural and adhesive properties relevant in disease.
Collapse
|
12
|
Nadar-Ponniah PT, Taiber S, Caspi M, Koffler-Brill T, Dror AA, Siman-Tov R, Rubinstein M, Padmanabhan K, Luxenburg C, Lang RA, Avraham KB, Rosin-Arbesfeld R. Striatin Is Required for Hearing and Affects Inner Hair Cells and Ribbon Synapses. Front Cell Dev Biol 2020; 8:615. [PMID: 32766247 PMCID: PMC7381154 DOI: 10.3389/fcell.2020.00615] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/22/2020] [Indexed: 12/22/2022] Open
Abstract
Striatin, a subunit of the serine/threonine phosphatase PP2A, is a core member of the conserved striatin-interacting phosphatase and kinase (STRIPAK) complexes. The protein is expressed in the cell junctions between epithelial cells, which play a role in maintaining cell-cell adhesion. Since the cell junctions are crucial for the function of the mammalian inner ear, we examined the localization and function of striatin in the mouse cochlea. Our results show that in neonatal mice, striatin is specifically expressed in the cell-cell junctions of the inner hair cells, the receptor cells in the mammalian cochlea. Auditory brainstem response measurements of striatin-deficient mice indicated a progressive, high-frequency hearing loss, suggesting that striatin is essential for normal hearing. Moreover, scanning electron micrographs of the organ of Corti revealed a moderate degeneration of the outer hair cells in the middle and basal regions, concordant with the high-frequency hearing loss. Additionally, striatin-deficient mice show aberrant ribbon synapse maturation. Loss of the outer hair cells, combined with the aberrant ribbon synapse distribution, may lead to the observed auditory impairment. Together, these results suggest a novel function for striatin in the mammalian auditory system.
Collapse
Affiliation(s)
- Prathamesh T. Nadar-Ponniah
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shahar Taiber
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Michal Caspi
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tal Koffler-Brill
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Amiel A. Dror
- Department of Otolaryngology, Head and Neck Surgery, Galilee Medical Center, Nahariya, Israel
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Ronen Siman-Tov
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Moran Rubinstein
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Krishnanand Padmanabhan
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chen Luxenburg
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Richard A. Lang
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Karen B. Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
13
|
Ryoo D, Rydmark MO, Pang YT, Lundquist KP, Linke D, Gumbart JC. BamA is required for autotransporter secretion. Biochim Biophys Acta Gen Subj 2020; 1864:129581. [PMID: 32114025 DOI: 10.1016/j.bbagen.2020.129581] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 02/01/2020] [Accepted: 02/22/2020] [Indexed: 01/24/2023]
Abstract
BACKGROUND In Gram-negative bacteria, type Va and Vc autotransporters are proteins that contain both a secreted virulence factor (the "passenger" domain) and a β-barrel that aids its export. While it is known that the folding and insertion of the β-barrel domain utilize the β-barrel assembly machinery (BAM) complex, how the passenger domain is secreted and folded across the membrane remains to be determined. The hairpin model states that passenger domain secretion occurs independently through the fully-formed and membrane-inserted β-barrel domain via a hairpin folding intermediate. In contrast, the BamA-assisted model states that the passenger domain is secreted through a hybrid of BamA, the essential subunit of the BAM complex, and the β-barrel domain of the autotransporter. METHODS To ascertain the models' plausibility, we have used molecular dynamics to simulate passenger domain secretion for two autotransporters, EspP and YadA. RESULTS We observed that each protein's β-barrel is unable to accommodate the secreting passenger domain in a hairpin configuration without major structural distortions. Additionally, the force required for secretion through EspP's β-barrel is more than that through the BamA β-barrel. CONCLUSIONS Secretion of autotransporters most likely occurs through an incompletely formed β-barrel domain of the autotransporter in conjunction with BamA. GENERAL SIGNIFICANCE Secretion of virulence factors is a process used by practically all pathogenic Gram-negative bacteria. Understanding this process is a necessary step towards limiting their infectious capacity.
Collapse
Affiliation(s)
- David Ryoo
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, GA 30332, United States of America
| | | | - Yui Tik Pang
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30313, United States of America
| | - Karl P Lundquist
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, United States of America
| | - Dirk Linke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30313, United States of America.
| |
Collapse
|
14
|
Abstract
Hearing and balance rely on the transduction of mechanical stimuli arising from sound waves or head movements into electrochemical signals. This archetypal mechanoelectrical transduction process occurs in the hair-cell stereocilia of the inner ear, which experience continuous oscillations driven by undulations in the endolymph in which they are immersed. The filamentous structures called tip links, formed by an intertwined thread composed of an heterotypic complex of cadherin 23 and protocadherin 15 ectodomain dimers, connect each stereocilium to the tip of the lower sterocilium, and must maintain their integrity against continuous stimulatory deflections. By using single molecule force spectroscopy, here we demonstrate that in contrast to the case of classical cadherins, tip-link cadherins are mechanoresilient structures even at the exceptionally low Ca2+ concentration of the endolymph. We also show that the D101G deafness point mutation in cadherin 23, which affects a Ca2+ coordination site, exhibits an altered mechanical phenotype at the physiological Ca2+ concentration. Our results show a remarkable case of functional adaptation of a protein’s nanomechanics to extremely low Ca2+ concentrations and pave the way to a full understanding of the mechanotransduction mechanism mediated by auditory cadherins.
Collapse
|
15
|
Abstract
Auditory transduction is fast and sensitive owing to the direct detection of mechanical stimuli by hair cells, the sensory receptors of the internal ear. A study by Dionne et al. (2018) in this issue of Neuron suggests how signals propagate through tip links, the cadherin-based strands that gate mechanically sensitive channels.
Collapse
|
16
|
Elasticity of individual protocadherin 15 molecules implicates tip links as the gating springs for hearing. Proc Natl Acad Sci U S A 2019; 116:11048-11056. [PMID: 31072932 PMCID: PMC6561218 DOI: 10.1073/pnas.1902163116] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Our hearing depends on mechanosensitive channels in hair cells of the inner ear. Experiments suggest that each channel is opened by a “gating spring,” an elastic element that conveys displacement of a hair bundle to the channel. Appropriate stiffness of the gating spring permits the discrimination of different sound amplitudes; if the spring is too stiff, then a faint sound will elicit the same response as a loud sound, opening all of a cell’s channels. Although the tip link—a fine molecular filament—might be the gating spring, its properties have remained controversial. Using high-precision optical tweezers, we demonstrate that the mechanical properties of a tip link protein correlate with those of a gating spring in vivo. Hair cells, the sensory receptors of the inner ear, respond to mechanical forces originating from sounds and accelerations. An essential feature of each hair cell is an array of filamentous tip links, consisting of the proteins protocadherin 15 (PCDH15) and cadherin 23 (CDH23), whose tension is thought to directly gate the cell’s transduction channels. These links are considered far too stiff to represent the gating springs that convert hair bundle displacement into forces capable of opening the channels, and no mechanism has been suggested through which tip-link stiffness could be varied to accommodate hair cells of distinct frequency sensitivity in different receptor organs and animals. Consequently, the gating spring’s identity and mechanism of operation remain central questions in sensory neuroscience. Using a high-precision optical trap, we show that an individual monomer of PCDH15 acts as an entropic spring that is much softer than its enthalpic stiffness alone would suggest. This low stiffness implies that the protein is a significant part of the gating spring that controls a hair cell’s transduction channels. The tip link’s entropic nature then allows for stiffness control through modulation of its tension. We find that a PCDH15 molecule is unstable under tension and exhibits a rich variety of reversible unfolding events that are augmented when the Ca2+ concentration is reduced to physiological levels. Therefore, tip link tension and Ca2+ concentration are likely parameters through which nature tunes a gating spring’s mechanical properties.
Collapse
|
17
|
De-la-Torre P, Choudhary D, Araya-Secchi R, Narui Y, Sotomayor M. A Mechanically Weak Extracellular Membrane-Adjacent Domain Induces Dimerization of Protocadherin-15. Biophys J 2018; 115:2368-2385. [PMID: 30527337 PMCID: PMC6302040 DOI: 10.1016/j.bpj.2018.11.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/01/2018] [Accepted: 11/05/2018] [Indexed: 10/27/2022] Open
Abstract
The cadherin superfamily of proteins is defined by the presence of extracellular cadherin (EC) "repeats" that engage in protein-protein interactions to mediate cell-cell adhesion, cell signaling, and mechanotransduction. The extracellular domains of nonclassical cadherins often have a large number of EC repeats along with other subdomains of various folds. Protocadherin-15 (PCDH15), a protein component of the inner-ear tip link filament essential for mechanotransduction, has 11 EC repeats and a membrane adjacent domain (MAD12) of atypical fold. Here we report the crystal structure of a pig PCDH15 fragment including EC10, EC11, and MAD12 in a parallel dimeric arrangement. MAD12 has a unique molecular architecture and folds as a ferredoxin-like domain similar to that found in the nucleoporin protein Nup54. Analytical ultracentrifugation experiments along with size-exclusion chromatography coupled to multiangle laser light scattering and small-angle x-ray scattering corroborate the crystallographic dimer and show that MAD12 induces parallel dimerization of PCDH15 near its membrane insertion point. In addition, steered molecular dynamics simulations suggest that MAD12 is mechanically weak and may unfold before tip-link rupture. Sequence analyses and structural modeling predict the existence of similar domains in cadherin-23, protocadherin-24, and the "giant" FAT and CELSR cadherins, indicating that some of them may also exhibit MAD-induced parallel dimerization.
Collapse
Affiliation(s)
- Pedro De-la-Torre
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio
| | - Deepanshu Choudhary
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio
| | - Raul Araya-Secchi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; Structural Biophysics, Section for Neutron and X-ray Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Yoshie Narui
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio.
| |
Collapse
|
18
|
Jaiganesh A, Narui Y, Araya-Secchi R, Sotomayor M. Beyond Cell-Cell Adhesion: Sensational Cadherins for Hearing and Balance. Cold Spring Harb Perspect Biol 2018; 10:a029280. [PMID: 28847902 PMCID: PMC6008173 DOI: 10.1101/cshperspect.a029280] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cadherins form a large family of proteins often involved in calcium-dependent cellular adhesion. Although classical members of the family can provide a physical bond between cells, a subset of special cadherins use their extracellular domains to interlink apical specializations of single epithelial sensory cells. Two of these cadherins, cadherin-23 (CDH23) and protocadherin-15 (PCDH15), form extracellular "tip link" filaments that connect apical bundles of stereocilia on hair cells essential for inner-ear mechanotransduction. As these bundles deflect in response to mechanical stimuli from sound or head movements, tip links gate hair-cell mechanosensitive channels to initiate sensory perception. Here, we review the unusual and diverse structural properties of these tip-link cadherins and the functional significance of their deafness-related missense mutations. Based on the structural features of CDH23 and PCDH15, we discuss the elasticity of tip links and models that bridge the gap between the nanomechanics of cadherins and the micromechanics of hair-cell bundles during inner-ear mechanotransduction.
Collapse
Affiliation(s)
- Avinash Jaiganesh
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| | - Yoshie Narui
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| | - Raul Araya-Secchi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| |
Collapse
|
19
|
Dionne G, Qiu X, Rapp M, Liang X, Zhao B, Peng G, Katsamba PS, Ahlsen G, Rubinstein R, Potter CS, Carragher B, Honig B, Müller U, Shapiro L. Mechanotransduction by PCDH15 Relies on a Novel cis-Dimeric Architecture. Neuron 2018; 99:480-492.e5. [PMID: 30057206 PMCID: PMC6168201 DOI: 10.1016/j.neuron.2018.07.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 06/06/2018] [Accepted: 06/29/2018] [Indexed: 10/28/2022]
Abstract
The tip link, a filament formed by protocadherin 15 (PCDH15) and cadherin 23, conveys mechanical force from sound waves and head movement to open hair-cell mechanotransduction channels. Tip-link cadherins are thought to have acquired structural features critical for their role in mechanotransduction. Here, we biophysically and structurally characterize the unusual cis-homodimeric architecture of PCDH15. We show that PCDH15 molecules form double-helical assemblies through cis-dimerization interfaces in the extracellular cadherin EC2-EC3 domain region and in a unique membrane-proximal domain. Electron microscopy studies visualize the cis-dimeric PCDH15 assembly and reveal the PCDH15 extracellular domain as a parallel double helix with cis cross-bridges at the two locations we defined. The helical configuration suggests the potential for elasticity through helix winding and unwinding. Functional studies in hair cells show that mutations that perturb PCDH15 dimerization contacts affect mechanotransduction. Together, these data reveal the cis-dimeric architecture of PCDH15 and show that dimerization is critical for sensing mechanical stimuli.
Collapse
Affiliation(s)
- Gilman Dionne
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Micah Rapp
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Xiaoping Liang
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bo Zhao
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Guihong Peng
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Phinikoula S Katsamba
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Goran Ahlsen
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Rotem Rubinstein
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - Clinton S Potter
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Bridget Carragher
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Barry Honig
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA.
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
20
|
Jaiganesh A, De-la-Torre P, Patel AA, Termine DJ, Velez-Cortes F, Chen C, Sotomayor M. Zooming in on Cadherin-23: Structural Diversity and Potential Mechanisms of Inherited Deafness. Structure 2018; 26:1210-1225.e4. [PMID: 30033219 DOI: 10.1016/j.str.2018.06.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 03/22/2018] [Accepted: 06/08/2018] [Indexed: 12/18/2022]
Abstract
Cadherin-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 (Ca2+) coordination at the EC linker regions is key for tip-link elasticity and function. There are ∼116 sites in CDH23 affected by deafness-causing mutations, many of which alter conserved Ca2+-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 Ca2+-binding motif sequences and unusual secondary structure. Complementary experiments show deafness mutations' effects on stability and affinity for Ca2+. 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.
Collapse
Affiliation(s)
- Avinash Jaiganesh
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA; Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Pedro De-la-Torre
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA
| | - Aniket A Patel
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA
| | - Domenic J Termine
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA
| | - Florencia Velez-Cortes
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA
| | - Conghui Chen
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA; Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA.
| |
Collapse
|