Cryo-EM structures of the TMEM16A calcium-activated chloride channel

Dang, Shangyu; Feng, Shengjie; Tien, Jason; Peters, Christian J.; Bulkley, David; Lolicato, Marco; Zhao, Jianhua; Zuberbühler, Kathrin; Ye, Wenlei; Qi, Lixin; Chen, Tingxu; Craik, Charles S.; Jan, Yuhnung; Minor, Daniel L.; Cheng, Yifan

doi:10.1038/nature25024

Cited by 296 publications

(396 citation statements)

References 53 publications

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“…ANO6 functions as a lipid scramblase and Cl À channel, and other Anoctamins have also been reported to have some scramblase activity (Whitlock & Hartzell, 2017). The family consists of 10 members, with very limited information on their properties and cellular functions, except for ANO1 (Dang et al, 2017;Paulino et al, 2017), ANO2 (Huang et al, 2012), and ANO6 (Suzuki et al, 2010;Brunner et al, 2014;Alvadia et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Anoctamin 8 tethers endoplasmic reticulum and plasma membrane for assembly of Ca ²⁺ signaling complexes at the ER/PM compartment

et al. 2019

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Communication and material transfer between membranes and organelles take place at membrane contact sites (MCSs). MCSs between the ER and PM, the ER/PM junctions, are the sites where the ER Ca2+ sensor STIM1 and the PM Ca2+ influx channel Orai1 cluster. MCSs are formed by tether proteins that bridge the opposing membranes, but the identity and role of these tethers in receptor‐evoked Ca2+ signaling is not well understood. Here, we identified Anoctamin 8 (ANO8) as a key tether in the formation of the ER/PM junctions that is essential for STIM1‐STIM1 interaction and STIM1‐Orai1 interaction and channel activation at a ER/PM PI(4,5)P2‐rich compartment. Moreover, ANO8 assembles all core Ca2+ signaling proteins: Orai1, PMCA, STIM1, IP3 receptors, and SERCA2 at the ER/PM junctions to mediate a novel form of Orai1 channel inactivation by markedly facilitating SERCA2‐mediated Ca2+ influx into the ER. This controls the efficiency of receptor‐stimulated Ca2+ signaling, Ca2+ oscillations, and duration of Orai1 activity to prevent Ca2+ toxicity. These findings reveal the central role of MCSs in determining efficiency and fidelity of cell signaling.

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Section: Introductionmentioning

confidence: 99%

Anoctamin 8 tethers endoplasmic reticulum and plasma membrane for assembly of Ca ²⁺ signaling complexes at the ER/PM compartment

et al. 2019

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“…Both subunits are related by twofold symmetry and show very similar conformations (Brunner et al, 2014). Recently, the highresolution protein structure of TMEM16A is revealed by singleparticle cryoelectron microscopy (Dang et al, 2017;Paulino et al, 2017), which showed the TMEM16A transmembrane protein is a homodimer that resembles the lipid scramblase nhTMEM16 (Paulino et al, 2017). In this homodimer, each subunit contains cytosolic Nand C-terminal domains, a transmembrane unit consisting of ten membrane-spanning α-helices and an extracellular component (Paulino et al, 2017).…”

Section: Topologymentioning

confidence: 99%

“…of the ten transmembrane segments may affect the entry of permeant ions and the inner half of α6 acts as a gating element (Dang et al, 2017). However, the structural changes caused by ion permeation channels are still unclear.…”

Section: Perspectivementioning

confidence: 99%

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Recent advances in TMEM16A: Structure, function, and disease

Guo

Wang

et al. 2018

Journal Cellular Physiology

100

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TMEM16A (also known as anoctamin 1, ANO1) is the molecular basis of the calcium‐activated chloride channels, with ten transmembrane segments. Recently, atomic structures of the transmembrane domains of mouse TMEM16A (mTMEM16A) were determined by single‐particle electron cryomicroscopy. This gives us a solid ground to discuss the electrophysiological properties and functions of TMEM16A. TMEM16A is reported to be dually regulated by Ca2+ and voltage. In addition, the dysfunction of TMEM16A has been found to be involved in many diseases including cystic fibrosis, various cancers, hypertension, and gastrointestinal motility disorders. TMEM16A is overexpressed in many cancers, including gastrointestinal stromal tumors, gastric cancer, head and neck squamous cell carcinoma (HNSCC), colon cancer, pancreatic ductal adenocarcinoma, and esophageal cancer. Furthermore, overexpression of TMEM16A is related to the occurrence, proliferation, and migration of tumor cells. To date, several studies have shown that many natural compounds and synthetic compounds have regulatory effects on TMEM16A. These small molecule compounds might be novel drugs for the treatment of diseases caused by TMEM16A dysfunction in the future. In addition, recent studies have shown that TMEM16A plays different roles in different diseases through different signal transduction pathways. This review discusses the topology, electrophysiological properties, modulators and functions of TMEM16A in mediates nociception, gastrointestinal dysfunction, hypertension, and cancer and focuses on multiple regulatory mechanisms regarding TMEM16A.

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“…Ins (1,4,5)P3 binding to Ins (1,4,5)P3 receptors then triggers release of Ca 2+ from internal ER stores and initiates store-operated Ca 2+ entry. The resulting rise in cytosolic Ca 2+ activates Clflux because of conformational changes induced by direct binding of Ca 2+ to the ANO1 protein (20)(21)(22)(23)(24). Calmodulin is not required for channel activation (20,25).…”

Section: Introductionmentioning

confidence: 99%

A Network of Phosphatidylinositol 4,5-bisphosphate Binding Sites Regulate Gating of the Ca²⁺-activated Cl⁻ Channel ANO1 (TMEM16A)

Jiang

Cui

et al. 2019

Preprint

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ANO1 (TMEM16A) is a Ca 2+ -activated Clchannel that regulates diverse cellular functions including fluid secretion, neuronal excitability, and smooth muscle contraction. ANO1 is activated by elevation of cytosolic Ca 2+ and modulated by phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). Here we describe a closely concerted experimental and computational study, including electrophysiology, mutagenesis, functional assays, and extended sampling of lipid-protein interactions with molecular dynamics (MD) to characterize PI(4,5)P2 binding modes and sites on ANO1. ANO1 currents in excised inside-out patches activated by 270 nM Ca 2+ at +100 mV are increased by exogenous PI(4,5)P2with an EC50 = 1.24 µM. The effect of PI(4,5)P2 is dependent on membrane voltage and Ca 2+ and is explained by a stabilization of the ANO1 Ca 2+ -bound open state. Unbiased atomistic MD simulations with 1.4% PI(4,5)P2 in a phosphatidylcholine bilayer identified 8 binding sites with significant probability of binding PI(4,5)P2. Three of these sites captured 85% of all ANO1 -PI(4,5)P2interactions. Mutagenesis of basic amino acids near the membrane-cytosol interface found three regions of ANO1 critical for PI(4,5)P2 regulation that correspond to the same three sites identified by MD. PI(4,5)P2 is stabilized by hydrogen bonding between amino acid sidechains and phosphate/hydroxyl groups on PI(4,5)P2. Binding of PI(4,5)P2 alters the position of the cytoplasmic extension of TM6, which plays a crucial role in ANO1 channel gating, and increases the accessibility of the inner vestibule to Clions. We propose a model consisting of a network of three PI(4,5)P2 binding sites at the cytoplasmic face of the membrane allosterically regulating ANO1 channel gating.of the authors and does not necessarily represent the official views of the National Institutes of Health. We also acknowledge computing resources provided by Blue Waters at National Center for Supercomputing Applications, and Extreme Science and Engineering Discovery Environment (grant MCA06N060 to ET).

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Cryo-EM structures of the TMEM16A calcium-activated chloride channel

Cited by 296 publications

References 53 publications

Anoctamin 8 tethers endoplasmic reticulum and plasma membrane for assembly of Ca ²⁺ signaling complexes at the ER/PM compartment

Anoctamin 8 tethers endoplasmic reticulum and plasma membrane for assembly of Ca ²⁺ signaling complexes at the ER/PM compartment

Recent advances in TMEM16A: Structure, function, and disease

A Network of Phosphatidylinositol 4,5-bisphosphate Binding Sites Regulate Gating of the Ca²⁺-activated Cl⁻ Channel ANO1 (TMEM16A)

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Cryo-EM structures of the TMEM16A calcium-activated chloride channel

Cited by 296 publications

References 53 publications

Anoctamin 8 tethers endoplasmic reticulum and plasma membrane for assembly of Ca 2+ signaling complexes at the ER/PM compartment

Anoctamin 8 tethers endoplasmic reticulum and plasma membrane for assembly of Ca 2+ signaling complexes at the ER/PM compartment

Recent advances in TMEM16A: Structure, function, and disease

A Network of Phosphatidylinositol 4,5-bisphosphate Binding Sites Regulate Gating of the Ca2+-activated Cl− Channel ANO1 (TMEM16A)

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Anoctamin 8 tethers endoplasmic reticulum and plasma membrane for assembly of Ca ²⁺ signaling complexes at the ER/PM compartment

Anoctamin 8 tethers endoplasmic reticulum and plasma membrane for assembly of Ca ²⁺ signaling complexes at the ER/PM compartment

A Network of Phosphatidylinositol 4,5-bisphosphate Binding Sites Regulate Gating of the Ca²⁺-activated Cl⁻ Channel ANO1 (TMEM16A)