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Nisler CR, Narui Y, Scheib E, Choudhary D, Bowman JD, Mandayam Bharathi H, Lynch VJ, Sotomayor M. Interpreting the Evolutionary Echoes of a Protein Complex Essential for Inner-Ear Mechanosensation. Mol Biol Evol 2023; 40:7076419. [PMID: 36911992 PMCID: PMC10089651 DOI: 10.1093/molbev/msad057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 01/17/2023] [Accepted: 02/21/2023] [Indexed: 03/14/2023] Open
Abstract
The sensory epithelium of the inner ear, found in all extant lineages of vertebrates, has been subjected to over 500 million years of evolution, resulting in the complex inner ear of modern vertebrates. Inner-ear adaptations are as diverse as the species in which they are found, and such unique anatomical variations have been well studied. However, the evolutionary details of the molecular machinery that is required for hearing are less well known. Two molecules that are essential for hearing in vertebrates are cadherin-23 and protocadherin-15, proteins whose interaction with one another acts as the focal point of force transmission when converting sound waves into electrical signals that the brain can interpret. This interaction exists in every lineage of vertebrates, but little is known about the structure or mechanical properties of these proteins in most non-mammalian lineages. Here, we use various techniques to characterize the evolution of this protein interaction. Results show how evolutionary sequence changes in this complex affect its biophysical properties both in simulations and experiments, with variations in interaction strength and dynamics among extant vertebrate lineages. Evolutionary simulations also characterize how the biophysical properties of the complex in turn constrain its evolution and provide a possible explanation for the increase in deafness-causing mutants observed in cadherin-23 relative to protocadherin-15. Together, these results suggest a general picture of tip-link evolution in which selection acted to modify the tip-link interface, while subsequent neutral evolution combined with varying degrees of purifying selection drove additional diversification in modern tetrapods.
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Affiliation(s)
- Collin R Nisler
- Department of Chemistry and Biochemistry, The Ohio State University 484 W 12th Avenue, Columbus, OH 43210, USA.,Biophysics Graduate Program, The Ohio State University 484 W 12th Avenue, Columbus, OH 43210, USA
| | - Yoshie Narui
- Center for Electron Microscopy and Analysis, The Ohio State University 1275-1305 Kinnear Road, Columbus, OH 43212, USA
| | - Emily Scheib
- Department of Chemistry and Biochemistry, The Ohio State University 484 W 12th Avenue, Columbus, OH 43210, USA
| | - Deepanshu Choudhary
- Department of Chemistry and Biochemistry, The Ohio State University 484 W 12th Avenue, Columbus, OH 43210, USA
| | - Jacob D Bowman
- Department of Biological Sciences, University at Buffalo, SUNY, Buffalo, NY 14260, USA
| | - Harsha Mandayam Bharathi
- Department of Chemistry and Biochemistry, The Ohio State University 484 W 12th Avenue, Columbus, OH 43210, USA
| | - Vincent J Lynch
- Department of Biological Sciences, University at Buffalo, SUNY, Buffalo, NY 14260, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University 484 W 12th Avenue, Columbus, OH 43210, USA.,Biophysics Graduate Program, The Ohio State University 484 W 12th Avenue, Columbus, OH 43210, USA
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Scheib E, Nisler CR, Sotomayor M. Structure of a non-mammalian cadherin heterodimer suggests a general binding mechanism essential for hair-cell mechanotransduction. Biophys J 2023; 122:474a. [PMID: 36784441 DOI: 10.1016/j.bpj.2022.11.2540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Emily Scheib
- Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | | | - Marcos Sotomayor
- Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
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Neel BL, Nisler CR, Walujkar S, Araya-Secchi R, Sotomayor M. Elastic versus brittle mechanical responses predicted for dimeric cadherin complexes. Biophys J 2022; 121:1013-1028. [PMID: 35151631 PMCID: PMC8943749 DOI: 10.1016/j.bpj.2022.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/02/2022] [Accepted: 02/07/2022] [Indexed: 12/15/2022] Open
Abstract
Cadherins are a superfamily of adhesion proteins involved in a variety of biological processes that include the formation of intercellular contacts, the maintenance of tissue integrity, and the development of neuronal circuits. These transmembrane proteins are characterized by ectodomains composed of a variable number of extracellular cadherin (EC) repeats that are similar but not identical in sequence and fold. E-cadherin, along with desmoglein and desmocollin proteins, are three classical-type cadherins that have slightly curved ectodomains and engage in homophilic and heterophilic interactions through an exchange of conserved tryptophan residues in their N-terminal EC1 repeat. In contrast, clustered protocadherins are straighter than classical cadherins and interact through an antiparallel homophilic binding interface that involves overlapped EC1 to EC4 repeats. Here we present molecular dynamics simulations that model the adhesive domains of these cadherins using available crystal structures, with systems encompassing up to 2.8 million atoms. Simulations of complete classical cadherin ectodomain dimers predict a two-phased elastic response to force in which these complexes first softly unbend and then stiffen to unbind without unfolding. Simulated α, β, and γ clustered protocadherin homodimers lack a two-phased elastic response, are brittle and stiffer than classical cadherins and exhibit complex unbinding pathways that in some cases involve transient intermediates. We propose that these distinct mechanical responses are important for function, with classical cadherin ectodomains acting as molecular shock absorbers and with stiffer clustered protocadherin ectodomains facilitating overlap that favors binding specificity over mechanical resilience. Overall, our simulations provide insights into the molecular mechanics of single cadherin dimers relevant in the formation of cellular junctions essential for tissue function.
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Affiliation(s)
- Brandon L Neel
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio
| | - Collin R Nisler
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; Biophysics Graduate Program, The Ohio State University, Columbus, Ohio
| | - Sanket Walujkar
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; Chemical Physics Graduate Program, The Ohio State University, Columbus, Ohio
| | - Raul Araya-Secchi
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago, Chile
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio; Biophysics Graduate Program, The Ohio State University, Columbus, Ohio; Chemical Physics Graduate Program, The Ohio State University, Columbus, Ohio.
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Neel BL, Nisler CR, Walujkar S, Araya-Secchi R, Sotomayor M. Collective mechanical responses of cadherin-based adhesive junctions as predicted by simulations. Biophys J 2022; 121:991-1012. [PMID: 35150618 PMCID: PMC8943820 DOI: 10.1016/j.bpj.2022.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/02/2022] [Accepted: 02/07/2022] [Indexed: 12/13/2022] Open
Abstract
Cadherin-based adherens junctions and desmosomes help stabilize cell-cell contacts with additional function in mechano-signaling, while clustered protocadherin junctions are responsible for directing neuronal circuits assembly. Structural models for adherens junctions formed by epithelial cadherin (CDH1) proteins indicate that their long, curved ectodomains arrange to form a periodic, two-dimensional lattice stabilized by tip-to-tip trans interactions (across junction) and lateral cis contacts. Less is known about the exact architecture of desmosomes, but desmoglein (DSG) and desmocollin (DSC) cadherin proteins are also thought to form ordered junctions. In contrast, clustered protocadherin (PCDH)-based cell-cell contacts in neuronal tissues are thought to be responsible for self-recognition and avoidance, and structural models for clustered PCDH junctions show a linear arrangement in which their long and straight ectodomains form antiparallel overlapped trans complexes. Here, we report all-atom molecular dynamics simulations testing the mechanics of minimalistic adhesive junctions formed by CDH1, DSG2 coupled to DSC1, and PCDHγB4, with systems encompassing up to 3.7 million atoms. Simulations generally predict a favored shearing pathway for the adherens junction model and a two-phased elastic response to tensile forces for the adhesive adherens junction and the desmosome models. Complexes within these junctions first unbend at low tensile force and then become stiff to unbind without unfolding. However, cis interactions in both the CDH1 and DSG2-DSC1 systems dictate varied mechanical responses of individual dimers within the junctions. Conversely, the clustered protocadherin PCDHγB4 junction lacks a distinct two-phased elastic response. Instead, applied tensile force strains trans interactions directly, as there is little unbending of monomers within the junction. Transient intermediates, influenced by new cis interactions, are observed after the main rupture event. We suggest that these collective, complex mechanical responses mediated by cis contacts facilitate distinct functions in robust cell-cell adhesion for classical cadherins and in self-avoidance signaling for clustered PCDHs.
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Affiliation(s)
- Brandon L Neel
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio
| | - Collin R Nisler
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; Biophysics Graduate Program, The Ohio State University, Columbus, Ohio
| | - Sanket Walujkar
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; Chemical Physics Graduate Program, The Ohio State University, Columbus, Ohio
| | - Raul Araya-Secchi
- Facultad de Ingenieria y Tecnologia, Universidad San Sebastian, Santiago, Chile
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; The Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio; Biophysics Graduate Program, The Ohio State University, Columbus, Ohio; Chemical Physics Graduate Program, The Ohio State University, Columbus, Ohio.
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Ahmed T, Nisler CR, Fluck EC, Walujkar S, Sotomayor M, Moiseenkova-Bell VY. Structure of the ancient TRPY1 channel from Saccharomyces cerevisiae reveals mechanisms of modulation by lipids and calcium. Structure 2022; 30:139-155.e5. [PMID: 34453887 PMCID: PMC8741645 DOI: 10.1016/j.str.2021.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/29/2021] [Accepted: 08/10/2021] [Indexed: 01/14/2023]
Abstract
Transient receptor potential (TRP) channels emerged in fungi as mechanosensitive osmoregulators. The Saccharomyces cerevisiae vacuolar TRP yeast 1 (TRPY1) is the most studied TRP channel from fungi, but the structure and details of channel modulation remain elusive. Here, we describe the full-length cryoelectron microscopy structure of TRPY1 at 3.1 Å resolution in a closed state. The structure, despite containing an evolutionarily conserved and archetypical transmembrane domain, reveals distinctive structural folds for the cytosolic N and C termini, compared with other eukaryotic TRP channels. We identify an inhibitory phosphatidylinositol 3-phosphate (PI(3)P) lipid-binding site, along with two Ca2+-binding sites: a cytosolic site, implicated in channel activation and a vacuolar lumen site, implicated in inhibition. These findings, together with data from microsecond-long molecular dynamics simulations and a model of a TRPY1 open state, provide insights into the basis of TRPY1 channel modulation by lipids and Ca2+, and the molecular evolution of TRP channels.
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Affiliation(s)
- Tofayel Ahmed
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Collin R Nisler
- Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sanket Walujkar
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Chemical Physics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Marcos Sotomayor
- Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA; Chemical Physics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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