Mechanical gating of the auditory transduction channel TMC1 involves the fourth and sixth transmembrane helices

Akyuz, Nurunisa; Karavitaki, K. Domenica; Pan, Bifeng; Tamvakologos, Panos I.; Brock, Kelly; Li, Yaqiao; Marks, Debora S.; Corey, David P.

doi:10.1126/sciadv.abo1126

Cited by 17 publications

(19 citation statements)

References 65 publications

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“…The shape of the activation curve and the bundle deflection at half activation in Pcdh15 R245X/+ control hair cells was similar to that reported previously in wild type mice using the same stimulation technique ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9278870/figure/F2/ Fig. 8f ) 54 . However, the activation curve of Pcdh15 R245/R245X hair cells expressing mini-PCDH15-V4 was shifted slightly to the right compared to Pcdh15 R245X/+ controls, likely a consequence of poor probe coupling to disorganized and off-axis hair bundles.…”

Section: Resultssupporting

confidence: 84%

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Mini-PCDH15 gene therapy rescues hearing in a mouse model of Usher syndrome type 1F

et al. 2023

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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.

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Section: Resultssupporting

confidence: 84%

“…Single cell electrophysiology was performed as described previously 54 . Neonatal P6 mice were anesthetized with cryoanesthesia and euthanized by decapitation.…”

Section: Methodsmentioning

confidence: 99%

Mini-PCDH15 gene therapy rescues hearing in a mouse model of Usher syndrome type 1F

et al. 2023

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“…Seven basic residues line the pore, two of which (H404 and H731) partially define the third and narrowest constriction site. Cysteine mutagenesis experiments have identified eight pore-lining residues in mouse TMC-1 7 , 45 and, although five of these residues are not conserved in C. elegans , the locations of all eight map to pore-lining positions in C. elegans TMC-1 (Extended Data Fig. 7a ), thus supporting their location in the ion-conduction pathway.…”

Section: Mapping the Putative Ion Channel Porementioning

confidence: 91%

Structures of the TMC-1 complex illuminate mechanosensory transduction

Jeong

Clark

Goehring

et al. 2022

Nature

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The initial step in the sensory transduction pathway underpinning hearing and balance in mammals involves the conversion of force into the gating of a mechanosensory transduction channel1. Despite the profound socioeconomic impacts of hearing disorders and the fundamental biological significance of understanding mechanosensory transduction, the composition, structure and mechanism of the mechanosensory transduction complex have remained poorly characterized. Here we report the single-particle cryo-electron microscopy structure of the native transmembrane channel-like protein 1 (TMC-1) mechanosensory transduction complex isolated from Caenorhabditis elegans. The two-fold symmetric complex is composed of two copies each of the pore-forming TMC-1 subunit, the calcium-binding protein CALM-1 and the transmembrane inner ear protein TMIE. CALM-1 makes extensive contacts with the cytoplasmic face of the TMC-1 subunits, whereas the single-pass TMIE subunits reside on the periphery of the complex, poised like the handles of an accordion. A subset of complexes additionally includes a single arrestin-like protein, arrestin domain protein (ARRD-6), bound to a CALM-1 subunit. Single-particle reconstructions and molecular dynamics simulations show how the mechanosensory transduction complex deforms the membrane bilayer and suggest crucial roles for lipid–protein interactions in the mechanism by which mechanical force is transduced to ion channel gating.

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“…Homology and experimental structural models for TMC1 and TMC2 have contributed to identifying a putative pore and providing insights into the ion permeation pathway 34,77,97,99 . Cryo-electron microscopy (Cryo-EM) structures of C. elegans ( Ce ) TMC1 confirmed at the atomic level the structural similarities between TMCs and TMEM16 and TMEM63/OSCA protein families 35,75,77,100 , which assemble as dimers with 10 (TMC1 and TMEM16) or 11 (TMEM63/OSCA) transmembrane (TM) domains in each subunit.…”

Section: Resultsmentioning

confidence: 99%

“…Subsequently, we utilized AlphaFold2-based structural predictions of the TMC1 protein in an open-like state 84 to carry out virtual screening (VS) of these 258 molecules, to predict their potential binding modes. Furthermore, we conducted a comparison of the 3D-pharmacophore features exhibited by TMC1 blockers with those of compounds reported to modulate the activity of the paralog TMEM16A protein, to identify potential structure-pharmacophoric relationships.…”

Section: Introductionmentioning

confidence: 99%

Identification of Druggable Binding Sites and Small Molecules as Modulators of TMC1

De-la-Torre,

Martínez-García,

Gratias

et al. 2024

Preprint

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The sensory hair cells of the inner ear use the mechano-electrical transducer (MET) channels to convert the mechanical stimuli from sound or acceleration into electrical signals, allowing us to perceive sound and maintain balance. The pore-forming subunit of the MET channel is formed by Transmembrane channel-like (TMC) 1 and 2 proteins, which are nonselective cationic channels that also allow the permeation of ototoxic aminoglycosides and cisplatin into hair cells. In search for otoprotective compounds, numerous molecules have been reported to block and modulate the properties of the MET channels. One of them, the styryl fluorescent probe FM1-43, and its analogue AM1-43, are commonly used to evaluate MET channel functionality. However, the mechanism of interaction of these modulators with the TMCs remains largely unknown. In this work, we implemented both computational and experimental approaches to identify novel TMC1 modulators using in silico 3D-pharmacophore approach and free energy binding calculations. Our 3D-pharmacophore contains the structural features necessary for ligands to bind and modulate the activity of TMC1. It consists of two aromatic groups, one acceptor group, and at least one protonatable amine. The pipeline we implemented successfully identified several novel TMC1 compound modulators, which reduced dye uptake in cultured cochlear explants, indicating MET modulation activity. Our molecular docking and MM-GBSA experiments allowed us to identify three potential drug binding sites within the TMC1 pore. Furthermore, our study also supports the ligand-binding relationship between the TMC and TMEM16 proteins, providing novel insights suggesting that these proteins share common 3D-pharmacophoric features for their inhibition.

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Mechanical gating of the auditory transduction channel TMC1 involves the fourth and sixth transmembrane helices

Cited by 17 publications

References 65 publications

Mini-PCDH15 gene therapy rescues hearing in a mouse model of Usher syndrome type 1F

Mini-PCDH15 gene therapy rescues hearing in a mouse model of Usher syndrome type 1F

Structures of the TMC-1 complex illuminate mechanosensory transduction

Identification of Druggable Binding Sites and Small Molecules as Modulators of TMC1

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