Syntaxin11 Deficiency Inhibits CRAC Channel Priming To Suppress Cytotoxicity And Gene Expression In FHLH4 Patient T Lymphocytes.

CRAC channels enable calcium entry from the extracellular space in response to a variety of stimuli and are crucial for gene expression and granule exocytosis in lymphocytes. Here we find that Syntaxin11, a Q-SNARE, associated with FHLH4 disease in human patients, directly binds Orai1, the pore forming subunit of CRAC channels. Syntaxin11 depletion strongly inhibited SOCE, CRAC currents, IL-2 expression and cytotoxicity in cell lines and FHLH4 patient T lymphocytes.

Integration of satellite remote sensing and MaxEnt modeling for improved detection and management of forest pests.

Forest pests pose a major threat to ecosystem services worldwide, requiring effective monitoring and management strategies. Recently, satellite remote sensing has emerged as a valuable tool to detect defoliation caused by these pests. Lymantria dispar, a major forest pest native to Japan, Siberia, and Europe, as well as introduced regions in North America, is of particular concern.

Carbapenemase-producing Enterobacterales isolated from hospital sinks: molecular relationships with isolates from patients and the change in contamination status after daily disinfection with sodium hypochlorite.

Objective: This study aimed to investigate the contamination status of hospital sinks with carbapenemase-producing Enterobacterales (CPE), the efficacy of daily cleaning with sodium hypochlorite, and the relationships between CPEs isolated from contaminated sinks and patients.

Design: Pre/postintervention surveys of the CPE-contaminated sinks.

Setting: Hospital wards including pediatric intensive care unit in a children's hospital.

A pathogenic human Orai1 mutation unmasks STIM1-independent rapid inactivation of Orai1 channels.

Ca release-activated Ca (CRAC) channels are activated by direct physical interactions between Orai1, the channel protein, and STIM1, the endoplasmic reticulum Ca sensor. A hallmark of CRAC channels is fast Ca-dependent inactivation (CDI) which provides negative feedback to limit Ca entry through CRAC channels. Although STIM1 is thought to be essential for CDI, its molecular mechanism remains largely unknown.

Store-operated calcium entry controls innate and adaptive immune cell function in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is characterized by dysregulated intestinal immune responses. Using mass cytometry (CyTOF) to analyze the immune cell composition in the lamina propria (LP) of patients with ulcerative colitis (UC) and Crohn's disease (CD), we observed an enrichment of CD4 effector T cells producing IL-17A and TNF, CD8 T cells producing IFNγ, T regulatory (Treg) cells, and innate lymphoid cells (ILC). The function of these immune cells is regulated by store-operated Ca entry (SOCE), which results from the opening of Ca release-activated Ca (CRAC) channels formed by ORAI and STIM proteins.

Cavβ1 regulates T cell expansion and apoptosis independently of voltage-gated Ca channel function.

TCR stimulation triggers Ca signals that are critical for T cell function and immunity. Several pore-forming α and auxiliary β subunits of voltage-gated Ca channels (VGCC) were reported in T cells, but their mechanism of activation remains elusive and their contribution to Ca signaling in T cells is controversial. We here identify Caβ1, encoded by Cacnb1, as a regulator of T cell function.

Interrogating permeation and gating of Orai channels using chemical modification of cysteine residues.

Chemical modification of ion channels using the substituted cysteine accessibility method has a rich and successful history in elucidating the structural basis of ion channel function. In this approach, cysteine residues are introduced in regions of interest into the protein and their accessibility to water soluble thiol-reactive reagents is determined by monitoring ion channel activity. Because a wide range of these reagents are available with differing size, charge, and membrane solubility, the physio-chemical environment of the introduced cysteine residue and therefore the protein domain of interest can be probed with great precision.

An open pore structure of the Orai channel, finally.

Store-operated Orai channels are a primary mechanism for mobilizing Ca signals in both non-excitable cells and excitable cells. The structure of the open channel, vital for understanding the mechanism of channel opening, is incompletely understood. We highlight a new study that unveils the structure of a constitutively active Orai mutant and takes us closer towards understanding the molecular basis of Orai channel activation.

Orai1 Channels Are Essential for Amplification of Glutamate-Evoked Ca Signals in Dendritic Spines to Regulate Working and Associative Memory.

Store-operated Orai1 calcium channels function as highly Ca-selective ion channels and are broadly expressed in many tissues including the central nervous system, but their contributions to cognitive processing are largely unknown. Here, we report that many measures of synaptic, cellular, and behavioral models of learning are markedly attenuated in mice lacking Orai1 in forebrain excitatory neurons. Results with focal glutamate uncaging in hippocampal neurons support an essential role of Orai1 channels in amplifying NMDA-receptor-induced dendritic Ca transients that drive activity-dependent spine morphogenesis and long-term potentiation at Schaffer collateral-CA1 synapses.

A sulfur-aromatic gate latch is essential for opening of the Orai1 channel pore.

Sulfur-aromatic interactions occur in the majority of protein structures, yet little is known about their functional roles in ion channels. Here, we describe a novel molecular motif, the M101 gate latch, which is essential for gating of human Orai1 channels via its sulfur-aromatic interactions with the F99 hydrophobic gate. Molecular dynamics simulations of different Orai variants reveal that the gate latch is mostly engaged in open but not closed channels.

Regulation of chemoconvulsant-induced seizures by store-operated Orai1 channels.

Key Points: Temporal lobe epilepsy is a complex neurological disease caused by imbalance of excitation and inhibition in the brain. Growing literature implicates altered Ca signalling in many aspects of epilepsy but the diversity of Ca channels that regulate this syndrome are not well-understood. Here, we report that mice lacking the store-operated Ca channel, Orai1, in the brain show markedly stronger seizures in response to the chemoconvulsants, kainic acid and pilocarpine.

Effects of climatic elements on Salmonella contamination in broiler chicken meat in Japan.

The effects of climatic elements on Salmonella contamination of chicken meat were investigated. Logistic regression analysis was performed to evaluate the association between Salmonella isolation, for 240 chicken samples purchased from March 2015 to February 2017, and climatic elements, over 65 days of chicken rearing. Salmonella was isolated from 143 samples (59.

The basic residues in the Orai1 channel inner pore promote opening of the outer hydrophobic gate.

Store-operated Orai1 channels regulate a wide range of cellular functions from gene expression to cell proliferation. Previous studies have shown that gating of Orai1 channels is regulated by the outer pore residues V102 and F99, which together function as a hydrophobic gate to block ion conduction in resting channels. Opening of this gate occurs through a conformational change that moves F99 away from the permeation pathway, leading to pore hydration and ion conduction.

Molecular basis of allosteric Orai1 channel activation by STIM1.

Store-operated Ca entry through Orai1 channels is a primary mechanism for Ca entry in many cells and mediates numerous cellular effector functions ranging from gene transcription to exocytosis. Orai1 channels are amongst the most Ca -selective channels known and are activated by direct physical interactions with the endoplasmic reticulum Ca sensor stromal interaction molecule 1 (STIM1) in response to store depletion triggered by stimulation of a variety of cell surface G-protein coupled and tyrosine kinase receptors. Work in the last decade has revealed that the Orai1 gating process is highly cooperative and strongly allosteric, likely driven by a wave of interdependent conformational changes throughout the protein originating in the peripheral C-terminal ligand binding site and culminating in pore opening.

Mapping the functional anatomy of Orai1 transmembrane domains for CRAC channel gating.

Store-operated Orai1 channels are activated through a unique inside-out mechanism involving binding of the endoplasmic reticulum Ca sensor STIM1 to cytoplasmic sites on Orai1. Although atomic-level details of Orai structure, including the pore and putative ligand binding domains, are resolved, how the gating signal is communicated to the pore and opens the gate is unknown. To address this issue, we used scanning mutagenesis to identify 15 residues in transmembrane domains (TMs) 1-4 whose perturbation activates Orai1 channels independently of STIM1.

ORAI2 modulates store-operated calcium entry and T cell-mediated immunity.

Store-operated Ca entry (SOCE) through Ca release-activated Ca (CRAC) channels is critical for lymphocyte function and immune responses. CRAC channels are hexamers of ORAI proteins that form the channel pore, but the contributions of individual ORAI homologues to CRAC channel function are not well understood. Here we show that deletion of Orai1 reduces, whereas deletion of Orai2 increases, SOCE in mouse T cells.

STIM1 activates CRAC channels through rotation of the pore helix to open a hydrophobic gate.

Store-operated Ca release-activated Ca (CRAC) channels constitute a major pathway for Ca influx and mediate many essential signalling functions in animal cells, yet how they open remains elusive. Here, we investigate the gating mechanism of the human CRAC channel Orai1 by its activator, stromal interacting molecule 1 (STIM1). We find that two rings of pore-lining residues, V102 and F99, work together to form a hydrophobic gate.

Pore opening mechanism of CRAC channels.

Three decades ago, James W. Putney Jr. conceptualized the idea of store-operated calcium entry (SOCE) to explain how depletion of endoplasmic reticulum (ER) Ca stores evokes Ca influx across the plasma membrane.

Depletion of H2S during obesity enhances store-operated Ca2+ entry in adipose tissue macrophages to increase cytokine production.

The increased production of proinflammatory cytokines by adipose tissue macrophages (ATMs) contributes to chronic, low-level inflammation during obesity. We found that obesity in mice reduced the bioavailability of the gaseous signaling molecule hydrogen sulfide (H2S). Steady-state, intracellular concentrations of H2S were lower in ATMs isolated from mice with diet-induced obesity than in ATMs from lean mice.