Structural basis for excitatory neuropeptide signaling

Nature Structural & Molecular Biology, Journal Year: 2024, Volume and Issue: 31(4), P. 717 - 726

Published: Feb. 9, 2024

Rapid signaling between neurons is mediated by ligand-gated ion channels, cell-surface proteins with an extracellular ligand-binding domain and a membrane-spanning channel domain. The degenerin/epithelial sodium (DEG/ENaC) superfamily diverse in terms of its gating stimuli, some DEG/ENaCs gated neuropeptides, others pH, mechanical force or enzymatic activity. mechanism which ligands bind to activate poorly understood. Here we dissected the structural basis for neuropeptide-gated activity DEG/ENaC, FMRFamide-gated 1 (FaNaC1) from annelid worm Malacoceros fuliginosus, using cryo-electron microscopy. Structures FaNaC1 ligand-free resting state several ligand-bound states reveal site capture ligand-induced conformational changes gating, verified complementary mutagenesis experiments. Our results illuminate offer template experimental dissection pharmacology conduction.

Language: Английский

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The bile acid-sensitive ion channel is gated by Ca2+-dependent conformational changes in the transmembrane domain

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 12, 2025

Summary The bile acid-sensitive ion channel (BASIC) is the least understood member of mammalian epithelial Na + channel/degenerin (ENaC/DEG) superfamily channels, which are involved in a variety physiological processes. While some members this superfamily, including BASIC, inhibited by extracellular Ca 2+ (Ca ), molecular mechanism underlying modulation remains unclear. Here, determining structure human BASIC presence and absence using single particle cryo-electron microscopy (cryo-EM), we reveal -dependent conformational changes transmembrane domain β-linkers. Electrophysiological experiments further show that glutamate residue vestibule pore underpins -binding site, whose occupancy determines conformation therefore flow through channel. These results principles governing gating its regulation ions, demonstrating ions modulate function via protein rather than solely from pore-block, as proposed for other superfamily.

Language: Английский

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Invertebrate Bile Acid‐Sensitive Ion Channels and Their Emergence in Bilateria

The FASEB Journal, Journal Year: 2025, Volume and Issue: 39(8)

Published: April 16, 2025

ABSTRACT The broad Degenerin/epithelial sodium channel (DEG/ENaC) family includes a subfamily of bile acid‐sensing ion channels (BASICs). While their biophysical properties are extensively studied in mammals, the presence and function BASICs invertebrates remain largely unexplored. Here, we present first functional evidence invertebrate BASICs, revealing conserved features evolutionary adaptations across bilaterian species. Using electrophysiological pharmacological approaches, show that exhibit species‐specific acid sensitivity profiles differing responses to blockers, amiloride, diminazene, while retaining shared like inhibition by calcium ions selective permeability ions. For example, acorn worm Schizocardium californicum BASIC displays similar brachiopod Novocrania anomala is activated solely ursodeoxycholic (UDCA) our experiments. Mutagenesis D444 residue pore‐lining region confirms its critical role gating. Combined phylogenetic analysis suggests emerged early evolution, evolving from were merely modulated acids, cousins, into acids. Tissue‐specific expression patterns imply roles acid‐dependent absorption or environmental sensing acid‐like compounds. Given absence endogenous acids invertebrates, propose may detect compounds, contributing ecological interactions. This study enhances understanding evolutionary, functional, with implications for future research native ligands.

Language: Английский

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Role of epithelial sodium channel-related inflammation in human diseases

Frontiers in Immunology, Journal Year: 2023, Volume and Issue: 14

Published: July 25, 2023

The epithelial sodium channel (ENaC) is a heterotrimer and widely distributed throughout the kidneys, blood vessels, lungs, colons, many other organs. basic role of ENaC to mediate entry Na + into cells; also has an important regulatory function in pressure, airway surface liquid (ASL), endothelial cell function. Aldosterone, serum/glucocorticoid kinase 1 (SGK1), shear stress, posttranslational modifications can regulate activity ENaC; some ion channels interact with ENaC. In recent years, it been found that lead immune activation, dysfunction, aggravated inflammation involved high salt-induced hypertension, cystic fibrosis, pseudohypoaldosteronism (PHA), tumors; inflammatory cytokines have reported on hyperfunction mediates increase intracellular , elevated exchange Ca 2+ leads calcium overload, which mechanism for ENaC-related inflammation. Some research controversial or unclear; we therefore reviewed progress studies human diseases their mechanisms.

Language: Английский

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Diarylamidine activation of a brachiopod DEG/ENaC/ASIC channel

Journal of Biological Chemistry, Journal Year: 2024, Volume and Issue: unknown, P. 108066 - 108066

Published: Dec. 1, 2024

Language: Английский

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The TWK-26 potassium channel governs nutrient absorption in theC. elegansintestine

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: May 7, 2024

ABSTRACT Ion channels are necessary for proper water and nutrient absorption in the intestine, which supports cellular metabolism organismal growth. While a role Na + co-transporters pumps intestinal is well defined, how individual K uniporters function to maintain ion homeostasis poorly understood. Using Caenorhabditis elegans , we show that gain-of-function mutation twk-26 encodes two-pore domain channel orthologous human KCNK3, facilitates suppresses metabolic developmental defects displayed by impaired MAP Kinase (MAPK) signaling. Mutations drl-1 flr-4, encode two components of this MAPK pathway, cause severe growth defects, reduced lipid storage, dramatic increase autophagic lysosomes, mirror dietary restriction phenotypes. Additionally, these mutants display structural intestine an defecation motor program. We find activation TWK-26 reverses restriction-like state restoring without correcting bloating or defects. This study provides unique insight into mechanisms support homeostasis.

Language: Английский

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Diarylamidine activation of a brachiopod DEG/ENaC/ASIC channel

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Aug. 26, 2024

Abstract Diarylamidines are a group of widely used small molecule drugs. One common use diarylamidines is their pharmacological inhibition ligand-gated cation channels, including tetrameric ionotropic glutamate receptors and trimeric degenerin/epithelial sodium channel channel/acid-sensing ion channels (DEG/ENaC/ASICs). Here, we discover DEG/ENaC/ASIC from the brachiopod (lamp shell) Novocrania anomala , at which act as agonists. The closely related to bile acid-gated, pH-gated, peptide-gated but not activated by such stimuli. We describe activation diminazene, DAPI, pentamidine, examine several biophysical properties, briefly explore molecular determinants activity with site-directed mutagenesis. term this diarylamidine-activated (DiaaNaC).

Language: Английский

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Ion channels and transporters keep ideas flowing

The Journal of Physiology, Journal Year: 2023, Volume and Issue: 601(9), P. 1517 - 1519

Published: April 3, 2023

In biological membranes, channels and transporters underlie essential processes that both mediate impact crucial communications between the intracellular extracellular milieus. Their functional impairment disrupts cellular signalling homeostasis, ultimately translating into systemic dysfunction disease. Similarly, disrupted function befell collective research endeavour with onset of coronavirus disease 2019 pandemic its imposition isolation. For most academic researchers, this effectively ceased not only wet-bench experimentation required to collect data, but also face-to-face exchange knowledge. Although information famine challenged researchers at all stages, effects isolation on junior investigators carried particularly damaging potential. The virtual Themed Meeting, ‘New Roles for Ion Channels Transporters in Health Disease’, was conceived as a means sustain community keep it strong. By bridging gap imposed by social isolation, meeting created forum attendees continue learning from–and be inspired by–colleagues near far. Perhaps more importantly, enthusiastic reception revealed underscored intangible benefit provided from feeling part dynamic community. With Special Issue, we leverage momentum gained Meeting. It offers symposium reviews topical pertinent theme. This issue comprises primary papers emerging groups settling back experimental mode–the products inspiration, renewed resolve tested resilience. an insightful review, Margarida Amaral reflects strategic patterns used generating recent body cystic fibrosis (CF), resulting impaired transmembrane conductance regulator (CFTR) function. relative merits emergent ‘omics’-based approaches (transcriptomics, proteomics, genomics interactomics) are weighed against hypothesis-driven driving rational drug design, well contrasting high-throughput screening identify pharmacotherapies (Amaral, 2023). doing so, based targeting CFTR, rescuing fluid secretion defect associated CF identifying alternative Cl− transport pathways. Thus, example provides object lesson strategies tackling diverse questions. contrast CFTR disease, aberrantly enhanced activity characterizes certain cancers. case gastrointestinal cancers, human ether-à-go-go related gene 1 (hERG1; KV11.1) K+ can drive tumour progression canonical non-canonical means. Arcangeli & colleagues (2023) discuss how association hERG1 β1-integrin subunit recruit membrane receptors, additional ion i.e. Na+/H+ exchanger (NHE1) neonatal form voltage-dependent Na+ channel (nNaV1.5), adhesion molecules. macromolecular complexes promotes cancer (Arcangeli et al., Interestingly, overexpressed KV11 capable conferring resonance potential oscillations (Matsuoka 2021). begs provocative question: do modulate within complexes? Leslie Brackenbury explore importance homeostasis breast tumours. model interweaves actions Na+/K+-ATPase, NHE1, Na+–HCO3− cotransporter (NBCn1), Na+-coupled glucose amino acid transporters, epithelial (ENaC), voltage-gated sodium (i.e. NaV1.5). exception raise Na+. Moreover, NHE1 NBCn1 concomitantly acidify pH. Taken together, explain observations high concentrations low pH tumours (Leslie Brackenbury, systematic Kaulich coworkers broadly cover topic degenerin (DEG)/ENaCs. review bridges work arising genetic electrophysiological approaches, highlighting roles DEG/ENaCs manifold modes sensation, addition their therapeutic targets (Kaulich, Grundy Stephan Gründer recounts his presentation, providing detailed treatment structural basis diversity neuropeptide gating invertebrate DEG/ENaC family members (Gründer 2022). he presents evidence demonstrating modulation, rather than gating, distinct regions vertebrate acid-sensing (ASICs). process likely involves stabilization either open or closed states. Emergent insights hold implications understanding endogenous neuropeptides (including opioid endorphins, such dynorphins) influence physiological via ASIC channels. paper focusing further DEG/ENaCs, Kaulich, McCubbin al. report Caenorhabditis elegans members. These authors leveraged automated voltage-clamp screening, comprehensively profiling sensitivity members, novel acid-activated acid-inhibited Obergrussberger (2022) recently demonstrated amenability other specifically ASIC1, high-throughput, patch-clamp (APC) recording. Applying knowledge discussed (2022), these capabilities enable pharmacology, gain modulation kinetics comprehensive panels neuropeptides. Summarily, ample opportunities understand properties enabling them behave successful sensors throughout animal kingdom. Endogenous metabolic byproducts regulate transporter activity. Combining molecular docking Rosenbaum laboratory transient receptor vallinoid 4 (TRPV4) cation single-channel probability lysophosphotidylcholine (LPC) metabolite, lysophosphotidic (LPA) (Benitez-Angeles TRPV4 expression epithelial, smooth muscle endothelial tissues organs skin lungs, suggests contributions LPC LPA tissue, organ whole-animal airways, proteins play key mediating host responses airborne stimuli, summarized Hollenhorst Krasteva-Christ (2023). Within respiratory tract, stimuli metabolites signal immune system bitter taste receptors specific cell types mouse upper lower airways (Hollenhorst Krasteva-Christ, initiating inflammatory responses, signals engage numerous two pore domain (K2P) Trpm5 channels), enhancing mucociliary clearance defense mechanisms. Insight many Piezo1, mechanosensitive gated forces pressure tension, is rapidly accumulating. eye, Piezo1 trabecular meshwork cells sensing intraocular regulating promoting outflow aqueous humour. Its role aetiology glaucoma, characterized inappropriate development pressure, unfolding steadily (Yarishkin our Barnett share discovery has functions very different namely myometrium. There, modulated protein kinase A/AKT/endothelial nitric oxide synthase-mediated paracrine microvascular endothelium uterine muscle, thereby ensuring quiescence during gestation. noteworthy less expressed myometrium women experiencing preterm labour. studies therefore reveal therapies mitigate condition extenuating consequences (Barnett To complement insights, accompanying Journal Club article (Majhi 2023) concisely thoroughly considers study Finally, surveying included note much what now known about arises studies. Such greatly readily available sequence drawn public databases. resources offer tempting shortcuts (such fragment synthesis) ‘old school’ cloning even PCR reverse-transcribed complementary DNA. However, treasure trove Pandora's box. convenient, construction plasmids directly synthesis using extracted genome sequencing unleash trouble downstream application data interpretation, Maxeiner pithy shares problems uninitiated might encounter, section subtitled ‘How avoid nasty surprises’ walks reader through avert disaster. Given sheer volume investigations reliant expression, cautious rigorous researcher would heed advice offered. collection articles maps potentially fruitful directions moving forwards equally impactful contexts. What physiological, pathophysiological environmental effector machinery? How does machinery scales, best each these? use treat disease? else learn omics-driven research? picture emerges taking context? We will know eventually, if strong ideas flowing. Please note: publisher responsible content functionality any supporting supplied authors. Any queries (other missing content) should directed corresponding author article. None. M.M.: Conception design work; Drafting revising critically important intellectual content; Final approval version published; Agreement accountable aspects P.F.: work.

Language: Английский

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Structural basis for excitatory neuropeptide signaling

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: April 29, 2023

ABSTRACT Rapid chemo-electric signaling between neurons is mediated by ligand-gated ion channels, cell-surface proteins with an extracellular ligand-binding domain and a membrane-spanning channel 1 . The degenerin/epithelial sodium (DEG/ENaC) superfamily, which occurs throughout the animal kingdom, unique in its diversity of gating stimuli, some DEG/ENaCs gated conventional ligands such as neuropeptides, others e.g. pH, mechanical force, or enzymatic activity 2-5 mechanism bind to activate poorly understood. We have therefore dissected structural basis for neuropeptide binding neuropeptide-gated DEG/ENaC, FMRFamide-gated (FaNaC1) from annelid worm Malacoceros fuliginosus 6 , using cryo-electron microscopy. High-resolution structures FaNaC1 ligand-free resting state several ligand-bound states reveal site capture ligand-induced conformational changes that mediate gating. Complementary mutagenesis experiments confirm functional roles particular amino acid residues implicated structures. Our results illuminate offer template experimental dissection pharmacology conduction characteristically metazoan superfamily.

Language: Английский

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