Ion channels

  • Article
    | Open Access

    GABAA receptors (GABAARs) cause inhibition in the brain by functioning as heteropentamers formed from multiple subunit types. Here, the authors demonstrate that receptors incorporating β3 subunits can spontaneously gate, which is modulated by protein kinases and neurosteroids to affect tonic inhibition.

    • Craig A. Sexton
    • , Reka Penzinger
    •  & Trevor G. Smart
  • Article
    | Open Access

    Volume-regulated anion channels (VRACs) are heteromers of LRRC8 proteins, all containing the obligatory subunit LRRC8A. Here, the authors develop and characterize nanobodies that bind LRRC8A and allosterically modulate the function of homomeric LRRC8A and endogenous heteromeric channels, hinting at functional mechanisms present in VRACs.

    • Dawid Deneka
    • , Sonja Rutz
    •  & Raimund Dutzler
  • Article
    | Open Access

    KdpFABC is a high-affinity bacterial K+ pump which combines the ion channel-like KdpA and the P-type ATPase KdpB. Here, the authors elucidate the mechanisms underlying transport and the coupling to ATP hydrolysis, and provide evidence that ions are transported via an intersubunit tunnel through KdpA and KdpB.

    • Jakob M. Silberberg
    • , Robin A. Corey
    •  & Inga Hänelt
  • Article
    | Open Access

    Strategies to improve the function of damaged hearts with progenitor cells have stalled. Here, the authors show that gene transfer of a calcium-dependent potassium channel enhances the functional properties and ability of explant-derived cells to improve heart function after a heart attack.

    • Patrick Vigneault
    • , Sandrine Parent
    •  & Stanley Nattel
  • Article
    | Open Access

    Hetero-oligomeric TRP-like channels such as PKD1L3/PKD2L1 play crucial roles in a range of physiological and pathophysiological processes. Here, the authors present the cryo-EM structures of a minimal functional murine PKD1L3/PKD2L1 complex in the absence and presence of calcium and further supported through structure-guided mutagenic studies, they discuss the mechanism of calcium-induced channel activation.

    • Qiang Su
    • , Mengying Chen
    •  & Yigong Shi
  • Article
    | Open Access

    Nicotinic acid adenine dinucleotide phosphate (NAADP) potent Ca2+ mobilizing second messenger which uniquely triggers Ca2+ release from acidic endolysosomal organelles. Here the authors identify Lsm12 as an NAADP receptor essential for NAADP-evoked Ca2+ release from lysosomes via NAADP binding on its Lsm domain.

    • Jiyuan Zhang
    • , Xin Guan
    •  & Jiusheng Yan
  • Article
    | Open Access

    Sea urchin hyperpolarization-activated cyclic nucleotide-gated (spHCN) ion channels channels are activated by membrane hyperpolarization instead of depolarization and undergo inactivation with hyperpolarization. Here authors apply transition metal ion FRET, patch-clamp fluorometry and Rosetta modeling to measure differences in the structural rearrangements between activation and inactivation of spHCN channels.

    • Gucan Dai
    • , Teresa K. Aman
    •  & William N. Zagotta
  • Article
    | Open Access

    Structural and functional characterization of the full-length TRPV1 channel from the thirteen-lined ground squirrel reveal the architecture of the extracellular cap domain and the intracellular C-terminus, and suggest a role of the cap domain in TRPV1 conductance and ion selectivity.

    • Kirill D. Nadezhdin
    • , Arthur Neuberger
    •  & Alexander I. Sobolevsky
  • Article
    | Open Access

    The lipid regulation of mammalian ion channel function has emerged as a fundamental mechanism in the control of electrical signalling and transport specificity. Here, the authors combine molecular dynamics simulations, mutagenesis, and electrophysiology to provide mechanistic insights into how lipophilic molecules alter gating kinetics and K+ currents of hERG1.

    • Williams E. Miranda
    • , Jiqing Guo
    •  & Sergei Yu. Noskov
  • Article
    | Open Access

    ORAI3 is part of pore forming calcium channels involved in T cell activation. Here the authors show that there is increased expression of ORAI3 in T cells from patients with rheumatoid arthritis and that the transcription factor IKAROS negatively regulates the ORAI3 promoter, indicating a regulatory loop that can control auto-reactivity of T cells in these patients.

    • Zhongde Ye
    • , Yi Shen
    •  & Jörg J. Goronzy
  • Article
    | Open Access

    The analysis of AMPA-type glutamate receptor (AMPAR) trafficking is essential for understanding molecular mechanisms of learning and memory, but the analytical tools are currently limited. Here, the authors report a method that combines affinity-based receptor labeling and bioorthogonal click chemistry to quantify AMPAR distribution and trafficking under physiological conditions.

    • Kento Ojima
    • , Kazuki Shiraiwa
    •  & Shigeki Kiyonaka
  • Article
    | Open Access

    Ryanodine Receptors (RyRs) release Ca2+ from the endoplasmic and sarcoplasmic reticulum. Mutations in RyR are linked to malignant hyperthermia (MH), myopathies, and arrhythmias. Here, a collection of cryoEM structures provides insights into the molecular consequences of MHrelated RyR mutation R615C, and how apoCaM opens RyR1.

    • Kellie A. Woll
    • , Omid Haji-Ghassemi
    •  & Filip Van Petegem
  • Article
    | Open Access

    The binding of cytoplasmic Ca2+ to the anion-selective channel TMEM16A triggers a conformational change around its binding site that is coupled to the release of a gate at the constricted neck. Here authors use cryo-EM and electrophysiology to identify three hydrophobic residues at the intracellular entrance of the neck as constituents of this gate.

    • Andy K. M. Lam
    • , Jan Rheinberger
    •  & Raimund Dutzler
  • Article
    | Open Access

    The anion channel TMEM16A is activated by intracellular Ca2+ in a highly cooperative process. Here authors combine electrophysiology and autocorrelation analysis to observe the sampling of intermediate conformations during gating.

    • Andy K. M. Lam
    •  & Raimund Dutzler
  • Article
    | Open Access

    Existing optogenetic methods to induce calcium mobilisation lack selectivity and specificity. Here, the authors design and engineer a single-component light-operated calcium channel to provide optical control over calcium signals and calcium-dependent physiological responses: LOCa.

    • Lian He
    • , Liuqing Wang
    •  & Yubin Zhou
  • Article
    | Open Access

    SthK, a cyclic nucleotide-gated ion channel from Spirochaeta thermophila activates slowly upon cAMP increase. Here, authors investigate cAMP-induced activation in purified SthK channels using stopped-flow assays and enzymatic catalysis and reveal that the cis/trans conformation of a conserved proline in the cyclic nucleotide-binding domain determines the activation kinetics of SthK.

    • Philipp A. M. Schmidpeter
    • , Jan Rheinberger
    •  & Crina M. Nimigean
  • Article
    | Open Access

    The involvement of cAMP-dependent regulation of HCN4 in the chronotropic heart rate response is a matter of debate. Here the authors use a knockin mouse model expressing cAMP-insensitive HCN4 channels to discover an inhibitory nonfiring cell pool in the sinoatrial node and a tonic and mutual interaction between firing and nonfiring pacemaker cells that is controlled by cAMP-dependent regulation of HCN4, with implications in chronotropic heart rate responses.

    • Stefanie Fenske
    • , Konstantin Hennis
    •  & Christian Wahl-Schott
  • Article
    | Open Access

    GABAA receptors mediate most inhibitory synaptic transmission in the brain. Here authors used concatemeric α1β2γ2 GABAA receptors to introduce gain-of-desensitization mutations one subunit at a time, revealing non-concerted rearrangements with a key contribution of the γ2 subunit during desensitization.

    • Marc Gielen
    • , Nathalie Barilone
    •  & Pierre-Jean Corringer
  • Article
    | Open Access

    Potassium ion channels control K+ permeation across cell membranes and mutations that cause cardiovascular and neural diseases are known. Here, the authors perform NMR measurements with the prototypical K+ channel from Streptomyces lividans, KcsA and characterise the effects of disease causing mutations on the conformational dynamics of K+ channels in a physiological solution environment.

    • Yuta Iwahashi
    • , Yuki Toyama
    •  & Ichio Shimada
  • Article
    | Open Access

    The TRPV1 ion channel is a heat-sensing receptor that is also activated by vanilloid compounds, but the molecular underpinnings of thermosensing have remained elusive. Here authors use in solution NMR on the isolated human TRPV1 S1-S4 domain and show that this domain undergoes a non-denaturing temperature-dependent transition with a high thermosensitivity.

    • Minjoo Kim
    • , Nicholas J. Sisco
    •  & Wade D. Van Horn
  • Article
    | Open Access

    Menthol in mints elicits a coolness sensation by selective activation of TRPM8 ion channel. Here authors dock menthol to TRPM8 and systematically validate their menthol binding models with thermodynamic mutant cycle analysis in functional tests, and shed light on TRPM8 activation by menthol at the atomic level.

    • Lizhen Xu
    • , Yalan Han
    •  & Fan Yang
  • Article
    | Open Access

    Glycinergic synapses play a central role in motor control and pain processing in the central nervous system. Here, authors present cryo-EM structures of the full-length glycine receptors (GlyRs) reconstituted into lipid nanodiscs in the unliganded, glycine-bound and allosteric modulator-bound conformations and reveal global conformational changes underlying GlyR channel gating and modulation.

    • Arvind Kumar
    • , Sandip Basak
    •  & Sudha Chakrapani
  • Article
    | Open Access

    Combining cryo-electron tomography with subtomogram averaging (StA) allows the in situ structure determination of proteins and protein complexes. Here, the authors present the hybrid StA (hStA) workflow that combines the advantages of single particle cryo-EM and StA and consists of a tomographic data collection scheme and a data processing workflow and they demonstrate how hStA can improve the resolution using two examples: the ion channel RyR1 and tobacco mosaic virus.

    • Ricardo M. Sanchez
    • , Yingyi Zhang
    •  & Mikhail Kudryashev
  • Article
    | Open Access

    Small molecule polyamines participate in diverse aspects of cell growth and differentiation and are known to regulate ion channel gating. Here authors reveal that cellular polyamines control nicotinic acetylcholine receptor (nAChR) biogenesis, and either catabolic degradation or inhibition of polyamine production augments nAChR assembly.

    • Madhurima Dhara
    • , Jose A. Matta
    •  & David S. Bredt
  • Article
    | Open Access

    The essential role of ORAI1 channels in receptor-evoked Ca2+ signaling is well understood, but the roles of ORAI2 and ORAI3 remained obscure. Here authors show that ORAI2 and ORAI3 channels multimerize with ORAI1 to expand the range of sensitivity of receptor-activated Ca2+ signals, reflecting their enhanced basal STIM1-binding and heightened Ca2+-dependent inactivation.

    • Ryan E. Yoast
    • , Scott M. Emrich
    •  & Mohamed Trebak
  • Article
    | Open Access

    The role of of voltage-gated sodium channels (Nav) in pacemaking and conduction of the human sinoatrial node is unclear. Here, the authors investigate existence and function of neuronal and cardiac Nav in human sinoatrial nodes, and demonstrate their alterations in explanted human diseased hearts.

    • Ning Li
    • , Anuradha Kalyanasundaram
    •  & Vadim V. Fedorov
  • Article
    | Open Access

    Type VI secretion systems (T6SSs) are used by bacteria to inject toxic effector proteins into neighbouring cells. Here, Mariano et al. show that an antibacterial effector from Serratia marcescens forms cation-selective pores that lead to inner-membrane depolarisation and increased outer-membrane permeability.

    • Giuseppina Mariano
    • , Katharina Trunk
    •  & Sarah J. Coulthurst
  • Article
    | Open Access

    Besides mechanical forces, the mechanosensitive channel Piezo1 is activated by the small molecule Yoda1 through an unknown mechanism. Here, using molecular dynamics simulations, calcium imaging and electrophysiology, the authors identify an allosteric Yoda1 binding pocket located in the putative mechanosensory domain.

    • Wesley M. Botello-Smith
    • , Wenjuan Jiang
    •  & Yun Luo
  • Article
    | Open Access

    The transient receptor potential channel member 2 (TRPM2) ion channel has a function in redox-dependent signaling. Here the authors present the cryo-EM structures of zebrafish TRPM2 in the ligand-free form, with Ca2+ and both ADP-ribose/Ca2+ and observe two-fold symmetric quaternary structure rearrangements in the ligand-bound structures that likely represent intermediate gating states.

    • Ying Yin
    • , Mengyu Wu
    •  & Seok-Yong Lee
  • Article
    | Open Access

    CASTOR is a Lotus japonicus ion channel required for nuclear Ca2+ spiking and establishing rhizobial and mycorrhizal symbioses. Here, via structural and functional analysis, Kim et al. show that CASTOR is a Ca2+-selective channel activated via Ca2+ binding to a soluble gating ring consisting of tandem RCK domains.

    • Sunghoon Kim
    • , Weizhong Zeng
    •  & Youxing Jiang
  • Article
    | Open Access

    The sinus node generates rhythmic heartbeat but the molecular basis of pacemaking is still under debate. Here, the authors combine quantitative proteomics and single-nucleus transcriptomics to characterize the molecular composition of the sinus node and provide insights into the underpinnings of pacemaking.

    • Nora Linscheid
    • , Sunil Jit R. J. Logantha
    •  & Alicia Lundby
  • Article
    | Open Access

    The leading cause of cystic fibrosis is the deletion of phenylalanine 508 (F508del) in the first nucleotide-binding domain (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR). Here authors we develop nanobodies targeting NBD1 of human CFTR and demonstrate their ability to stabilize both isolated NBD1 and full-length protein.

    • Maud Sigoillot
    • , Marie Overtus
    •  & Cedric Govaerts
  • Article
    | Open Access

    Endoplasmic reticulum Ca2+ sensing STIM proteins and plasma membrane Orai1 channels together regulate Ca2+ influx in eukaryotic cells. Here authors show that two Ca2+-dependent transcription factors, NFAT1 and c-fos, have different requirements for the number of STIM1-Orai1 clusters and on the Ca2+ flux through the clusters.

    • Yu-Ping Lin
    • , Daniel Bakowski
    •  & Anant B. Parekh
  • Article
    | Open Access

    Opening of G protein-gated inwardly rectifying potassium channels (GIRK) is coupled to the activation of a GPCR. Here the authors use NMR and cell-based BRET assays to gain insights into the mechanisms underlying family-specific activation and find that pre-formation of the Gαi/oβγ-GIRK complex in the inactive state is responsible for specific GIRK activation and present a structural model for the Gαi/oβγ-GIRK complex.

    • Hanaho Kano
    • , Yuki Toyama
    •  & Ichio Shimada
  • Article
    | Open Access

    TMEM16F is an enigmatic Ca2 + -activated phospholipid scramblase (CaPLSase) that passively transports phospholipids. Here authors identify an inner activation gate and its disruption profoundly alters TMEM16F phospholipid permeation.

    • Trieu Le
    • , Zhiguang Jia
    •  & Huanghe Yang
  • Article
    | Open Access

    G-protein-gated inward rectifying potassium channels (GIRKs) require Gβγ subunits and phosphorylated phosphatidylinositides (PIPs) for gating. Here authors use native ion mobility mass spectrometry to monitor small molecule binding events to GIRK2 and shed light on the selectivity of GIRK2 towards PIPs.

    • Yang Liu
    • , Catherine E. LoCaste
    •  & Arthur Laganowsky
  • Article
    | Open Access

    Piezo channels are mechanosensitive and rely on membrane composition to transduce physical stimuli into electrical signals. Here authors analyse the membrane components that modulate Piezo1 function using lipid profiling which shows that fatty acid metabolism can modulate ion channel activity.

    • Luis O. Romero
    • , Andrew E. Massey
    •  & Valeria Vásquez
  • Article
    | Open Access

    Two-photon absorption capacity of azobenzene photoswitches usually comes with a reduction in thermal stability. Here, the authors developed photoswitches with high two-photon sensitivity and enhanced cis isomer thermal lifetime for the control of glutamate receptors.

    • Gisela Cabré
    • , Aida Garrido-Charles
    •  & Ramon Alibés
  • Article
    | Open Access

    Allostery is a fundamental principle of protein regulation that remains challenging to engineer. Here authors screen human Inward Rectifier K + Channel Kir2.1 for permissibility to domain insertions and propose that differential permissibility is a metric of latent allosteric capacity in Kir2.1.

    • Willow Coyote-Maestas
    • , Yungui He
    •  & Daniel Schmidt
  • Article
    | Open Access

    Spontaneous activity shifts at constant experimental conditions are widespread among ion channels but the molecular origins are poorly understood. Here, using solid-state NMR and MD simulations, the authors reveal that modal gating shifts in K + channels are caused by large shifts in the channel dynamics which perturb the selectivity filter.

    • Shehrazade Jekhmane
    • , João Medeiros-Silva
    •  & Markus Weingarth
  • Article
    | Open Access

    The helical transmembrane segments of membrane proteins play central roles in sensory transduction but the mechanistic basis for their function remains unresolved. Here the authors identify regions in the S4 voltage-sensing segment of Shaker potassium channels where local helical structure is reliant upon backbone amide support.

    • Daniel T. Infield
    • , Kimberly Matulef
    •  & Francis I. Valiyaveetil
  • Article
    | Open Access

    In plants, hyperosmolality stimuli triggers opening of the osmosensitive channels, leading to a rapid downstream signaling cascade. Here, the authors solve the cryo-EM structure of an osmosensitive channel from Arabidopsis OSCA1.2 in its inactivated state.

    • Xin Liu
    • , Jiawei Wang
    •  & Linfeng Sun
  • Article
    | Open Access

    Transient receptor potential vanilloid channel 3 (TRPV3) responds to temperature and sensitizes upon repeated stimulation with either heat or agonists. Here authors present the cryo-EM structures of apo and sensitized human TRPV3 and describe the structural basis of sensitization.

    • Lejla Zubcevic
    • , Mark A. Herzik Jr.
    •  & Seok-Yong Lee
  • Article
    | Open Access

    Giant cell lesions of the jaw (GCLJ) are debilitating benign tumors of unclear origin. The authors identify driver recurrent somatic mutations in TRPV4, KRAS and FGFR1 and show they converge on aberrant activation of the MAPK pathway. Their findings extend the spectrum of TRPV4 channelopathies and provide rationale for targeted therapies at the bedside in GCLJ.

    • Carolina Cavalieri Gomes
    • , Tenzin Gayden
    •  & Nada Jabado