Voltage-activated potassium (Kv) channels open upon membrane depolarization and proceed to spontaneously inactivate. Inactivation controls neuronal firing rates serves as a form of short-term memory is implicated in various human neurological disorders. Here, we use high-resolution cryo–electron microscopy computer simulations determine one the molecular mechanisms underlying this physiologically crucial process. Structures activated Shaker Kv channel its W434F mutant lipid bilayers...

Voltage-activated potassium (Kv) channels open to conduct K+ ions in response membrane depolarization, and subsequently enter non-conducting states through distinct mechanisms of inactivation. X-ray structures detergent-solubilized Kv appear have captured an state even though a C-type inactivated would predominate membranes the absence transmembrane voltage. However, for voltage-activated ion channel lipid bilayer environment not yet been reported. Here we report structure Kv1.2–2.1 paddle...

Abstract The Kv2.1 voltage-activated potassium (Kv) channel is a prominent delayed-rectifier Kv in the mammalian central nervous system, where its mechanisms of activation and inactivation are critical for regulating intrinsic neuronal excitability 1,2 . Here we present structures lipid environment using cryo-electron microscopy to provide framework exploring functional how mutations causing epileptic encephalopathies 3–7 alter activity. By studying series disease-causing mutations,...

Venom toxins are invaluable tools for exploring the structure and mechanisms of ion channels. Here, we solve double-knot toxin (DkTx), a tarantula that activates heat-activated TRPV1 channel. We also provide improved structures with without bound, investigate interactions DkTx channel membranes. find binds to outer edge external pore in counterclockwise configuration, using limited protein-protein interface inserting hydrophobic residues into bilayer. show partitions naturally membranes, two...

Significance The TRPV1 channel is an important detector of noxious heat, yet the location heat sensor and mechanism activation remain poorly understood. Here we used structure-based engineering between heat-activated Shaker Kv to demonstrate that transplantation pore domain into gives rise functional channels can be activated by a TRPV1-selective tarantula toxin demonstrating contains structural elements sufficient for temperature.

TRPV1 channels in sensory neurons are integrators of painful stimuli and heat, yet how they integrate diverse sense temperature remains elusive. Here, we show that external sodium ions stabilize the channel a closed state, such removing ion leads to activation. In studying underlying mechanism, find sensors activate two steps favor opening, binding an extracellular site exerts allosteric control over temperature-sensor activation opening pore. The tarantula toxin pore also activation,...

The TRPV1 channel is a detector of noxious stimuli, including heat, acidosis, vanilloid compounds and lipids. gating mechanisms the related TRPV2 are poorly understood because selective high affinity ligands not available, threshold for heat activation extremely (>50°C). Cryo-EM structures reveal that they adopt similar structures, identify putative binding pocket near internal side TRPV1. Here we use biochemical electrophysiological approaches to investigate resiniferatoxin(RTx) site in...

The cation-permeable TRPV2 channel is important for cardiac and immune cell function. Cannabidiol (CBD), a non-psychoactive cannabinoid of clinical relevance, one the few molecules known to activate TRPV2. Using patch-clamp technique, we discover that CBD can sensitize current responses rat synthetic agonist 2-aminoethoxydiphenyl borate (2-APB) by over two orders magnitude, without sensitizing channels activation moderate (40°C) heat. cryo-EM, uncover new small-molecule binding site in pore...

Tarantula toxins that bind to voltage-sensing domains of voltage-activated ion channels are thought partition into the membrane and channel within bilayer. While no structures a voltage-sensor toxin bound have been solved, structural homolog, psalmotoxin (PcTx1), was recently crystalized in complex with extracellular domain an acid sensing (ASIC). In present study we use spectroscopic, biophysical computational approaches compare interaction properties binding surfaces PcTx1 guangxitoxin...

Voltage-activated ion channels open and close in response to changes membrane voltage, a property that is fundamental the roles of these electrical signaling. Protein toxins from venomous organisms commonly target S1–S4 voltage-sensing domains modify their gating properties. Studies on interaction hanatoxin with Kv2.1 channel show this tarantula toxin interacts domain inhibits opening by stabilizing closed state. Here we investigated Shaker Kv channel, voltage-activated has been extensively...

Eukaryotic voltage-gated K + channels have been extensively studied, but the structural bases for some of their most salient functional features remain to be established. C-type inactivation, example, is an auto-inhibitory mechanism that confers temporal resolution signal-firing activity. In a recent breakthrough, studies mutant Shaker prone inactivate indicated this process entails dilation selectivity filter, narrowest part ion conduction pathway. Here, we report atomic-resolution...

GxTX-1E is a neurotoxin recently isolated from Plesiophrictus guangxiensis venom that inhibits the Kv2.1 channel in pancreatic beta-cells. The sequence of toxin related to those previously studied tarantula toxins interact with voltage sensors Kv channels, and interacts unusually high affinity, making it particularly useful for structural mechanistic studies. Here we determined three-dimensional solution structure using NMR spectroscopy compared several toxins. molecular similar target...

A unique peptide toxin, named double-knot toxin (DkTx), was recently purified from the venom of tarantula Ornithoctonus huwena and found to stably activate TRPV1 channels by targeting outer pore domain. DkTx has been shown consist two inhibitory cysteine-knot (ICK) motifs, referred as K1 K2, each containing six cysteine residues. Beyond this initial characterization, however, structural functional details about remains elusive in large part due lack a high yielding methodology for synthesis...

Wnt proteins regulate a large number of processes, including cellular growth, differentiation, and tissue homeostasis, through the highly conserved signaling pathway in metazoans. Porcupine (PORCN) is an endoplasmic reticulum (ER)-resident integral membrane enzyme that catalyzes posttranslational modification Wnts with palmitoleic acid, unsaturated lipid. This unique form lipidation acid vital step biogenesis secretion Wnt, PORCN inhibitors are currently clinical trials for cancer treatment....

Background: Cancer-specific ligands have been of great interest as pharmaceutical carriers due to the potential for site-specific delivery. In particular, cancer-specific peptides many advantages over nanoparticles and antibodies, including high biocompatibility, low immunogenicity, formation nontoxic metabolites. The goal present study was development a novel ligand. Methods: peptide were screened using one-bead-one-compound (OBOC) combinatorial method combined with multiple-antigen-peptide...

Kurtoxin is a 63-amino acid polypeptide isolated from the venom of South African scorpion Parabuthus transvaalicus. It first and only peptide ligand known to interact with Cav3 (T-type) voltage-gated Ca(2+) channels high affinity modify voltage-dependent gating these channels. Here we describe nuclear magnetic resonance (NMR) solution structure kurtoxin determined using two- three-dimensional NMR spectroscopy dynamical simulated annealing calculations. The molecular toxin was highly similar...

The cation-permeable TRPV2 channel is essential for cardiac and immune cells. Cannabidiol (CBD), a non-psychoactive cannabinoid of clinical relevance, one the few molecules known to activate TRPV2. Using patch-clamp technique we discover that CBD can sensitize current responses rat synthetic agonist 2-aminoethoxydiphenyl borate (2- APB) by over two orders magnitude, without sensitizing channels activation moderate (40 ⁰C) heat. cryo-EM uncover new small-molecule binding site in pore domain...

Abstract Voltage-activated potassium (Kv) channels open upon membrane depolarization and proceed to spontaneously inactivate. Inactivation controls neuronal firing rates serves as a form of short-term memory, is implicated in various human neurological disorders. Here, we use high-resolution cryo-electron microscopy computer simulations determine one the molecular mechanisms underlying this physiologically crucial process. Structures activated Shaker Kv channel its W434F mutant lipid...