skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Tuning Inner-Ear Tip-Link Affinity Through Alternatively Spliced Variants of Protocadherin-15

Journal Article · · Biochemistry

Human hearing relies upon the tip-to-tip interaction of two nonclassical cadherins, protocadherin-15 (PCDH15) and cadherin-23 (CDH23). Together, these proteins form a filament called the tip link that connects neighboring stereocilia of mechanosensitive hair cells. As sound waves enter the cochlea, the stereocilia deflect and tension is applied to the tip link, opening nearby transduction channels. Disruption of the tip link by loud sound or calcium chelators eliminates transduction currents and illustrates that tip-link integrity is critical for mechanosensing. Tip-link remodeling after disruption is a dynamic process, which can lead to the formation of atypical complexes that incorporate alternatively spliced variants of PCDH15. These variants are categorized into six groups (N1–N6) based upon differences in the first two extracellular cadherin (EC) repeats. Here, we characterized the two N-terminal EC repeats of all PCDH15 variants (pcdh15(N1) to pcdh15(N6)) and combined these variants to test complex formation. We solved the crystal structure of a new complex composed of CDH23 EC1-2 (cdh23) and pcdh15(N2) at 2.3 Å resolution and compared it to the canonical cdh23–pcdh15(N1) complex. While there were subtle structural differences, the binding affinity between cdh23 and pcdh15(N2) is ~6 times weaker than cdh23 and pcdh15(N1) as determined by surface plasmon resonance analysis. Steered molecular dynamics simulations predict that the unbinding force of the cdh23–pcdh15(N2) complex can be lower than the canonical tip link. Our results demonstrate that alternative heterophilic tip-link structures form stable protein–protein interactions in vitro and suggest that homophilic PCDH15–PCDH15 tip links form through the interaction of additional EC repeats.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Organization:
National Institutes of Health (NIH); The Ohio State University; National Institute on Deafness and Other Communication Disorders (NIDCD); Alfred P. Sloan Fellow
Grant/Contract Number:
AC02-06CH11357; GUP 40277
OSTI ID:
1462552
Journal Information:
Biochemistry, Vol. 57, Issue 11; ISSN 0006-2960
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
ENGLISH
Citation Metrics:
Cited by: 11 works
Citation information provided by
Web of Science

References (48)

Cadherin 23 is a component of the tip link in hair-cell stereocilia journal March 2004
Cadherin 23 and protocadherin 15 interact to form tip-link filaments in sensory hair cells journal September 2007
Mutations in cadherin 23 affect tip links in zebrafish sensory hair cells journal March 2004
Beyond Cell–Cell Adhesion: Sensational Cadherins for Hearing and Balance journal August 2017
Cross-links between stereocilia in the guinea pig organ of Corti, and their possible relation to sensory transduction journal August 1984
High-resolution structure of hair-cell tip links journal November 2000
Localization of inner hair cell mechanotransducer channels using high-speed calcium imaging journal March 2009
Sensitivity, polarity, and conductance change in the response of vertebrate hair cells to controlled mechanical stimuli. journal June 1977
Regeneration of broken tip links and restoration of mechanical transduction in hair cells journal December 1996
Molecular Remodeling of Tip Links Underlies Mechanosensory Regeneration in Auditory Hair Cells journal June 2013
Direct mechanical stimulation of tip links in hair cells through DNA tethers journal June 2016
Mutations in Cdh23, encoding a new type of cadherin, cause stereocilia disorganization in waltzer, the mouse model for Usher syndrome type 1D journal January 2001
The mouse Ames waltzer hearing-loss mutant is caused by mutation of Pcdh15, a novel protocadherin gene journal January 2001
Mutation of CDH23, encoding a new member of the cadherin gene family, causes Usher syndrome type 1D journal January 2001
Usher Syndrome 1D and Nonsyndromic Autosomal Recessive Deafness DFNB12 Are Caused by Allelic Mutations of the Novel Cadherin-Like Gene CDH23 journal January 2001
Thinking outside the cell: how cadherins drive adhesion journal June 2012
Cadherins in Brain Morphogenesis and Wiring journal April 2012
Cross-links between stereocilia in the guinea pig cochlea journal May 1985
The dimensions and structural attachments of tip links in mammalian cochlear hair cells and the effects of exposure to different levels of extracellular calcium journal June 2008
Structure of a force-conveying cadherin bond essential for inner-ear mechanotransduction journal November 2012
Noddy, a Mouse Harboring a Missense Mutation in Protocadherin-15, Reveals the Impact of Disrupting a Critical Interaction Site between Tip-Link Cadherins in Inner Ear Hair Cells journal March 2013
Asymmetric distribution of cadherin 23 and protocadherin 15 in the kinocilial links of avian sensory hair cells journal July 2010
Regulation of PCDH15 function in mechanosensory hair cells by alternative splicing of the cytoplasmic domain journal March 2011
The CD 2 isoform of protocadherin‐15 is an essential component of the tip‐link complex in mature auditory hair cells journal June 2014
[20] Processing of X-ray diffraction data collected in oscillation mode book January 1997
REFMAC 5 for the refinement of macromolecular crystal structures journal March 2011
Molecular dynamics simulations in biology journal October 1990
Single-Molecule Experiments in Vitro and in Silico journal May 2007
VMD: Visual molecular dynamics journal February 1996
Scalable molecular dynamics with NAMD journal January 2005
CHARMM36 all-atom additive protein force field: Validation based on comparison to NMR data journal July 2013
An elastic element in the protocadherin-15 tip link of the inner ear journal November 2016
PCDH15 is expressed in the neurosensory epithelium of the eye and ear and mutant alleles are responsible for both USH1F and DFNB23 journal November 2003
Ca2+ Changes the Force Sensitivity of the Hair-Cell Transduction Channel journal January 2006
Compliance of the hair bundle associated with gating of mechanoelectrical transduction channels in the Bullfrog's saccular hair cell journal May 1988
Displacement-clamp measurement of the forces exerted by gating springs in the hair bundle. journal February 1993
Models for the specific adhesion of cells to cells journal May 1978
Mechanics of the Mammalian Cochlea journal July 2001
Alternative Splicing of Drosophila Dscam Generates Axon Guidance Receptors that Exhibit Isoform-Specific Homophilic Binding journal September 2004
A Vast Repertoire of Dscam Binding Specificities Arises from Modular Interactions of Variable Ig Domains journal September 2007
Neuroligin 1: A splice site-specific ligand for β-neurexins journal May 1995
A Splice Code for trans-Synaptic Cell Adhesion Mediated by Binding of Neuroligin 1 to α- and β-Neurexins journal October 2005
Tip-link integrity and mechanical transduction in vertebrate hair cells journal December 1991
Dynamic strength of molecular adhesion bonds journal April 1997
Highly efficient recovery of functional single-chain Fv fragments from inclusion bodies overexpressed in Escherichia coli by controlled introduction of oxidizing reagent—application to a human single-chain Fv fragment journal October 1998
A Close Look at Hearing Repair, One Protein at a Time journal June 2013
The Tip-Link Antigen, a Protein Associated with the Transduction Complex of Sensory Hair Cells, Is Protocadherin-15 journal June 2006
A Novel Antigen Sensitive to Calcium Chelation That is Associated with the Tip Links and Kinocilial Links of Sensory Hair Bundles journal June 2003

Cited By (1)

Inhibition of a transcriptional repressor rescues hearing in a splicing factor–deficient mouse journal October 2020