6mix

Human TRPM2 ion channel in apo stateHuman TRPM2 ion channel in apo state

6mix, resolution 3.60Å Show:Asymmetric Unit Biological Assembly Structural highlights 6mix is a 4 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.6Å Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TRPM2_HUMAN Isoform 1: Nonselective, voltage-independent cation channel that mediates Na(+) and Ca(2+) influx, leading to increased cytoplasmic Ca(2+) levels (PubMed:11960981, PubMed:12594222, PubMed:11385575, PubMed:11509734, PubMed:11804595, PubMed:15561722, PubMed:16601673, PubMed:19171771, PubMed:20660597, PubMed:27383051, PubMed:27068538). Extracellular calcium passes through the channel and increases channel activity by binding to the cytoplasmic domain and stabilizing the channel in an open conformation (PubMed:19171771). Also contributes to Ca(2+) release from intracellular stores in response to ADP-ribose (PubMed:19454650). Plays a role in numerous processes that involve signaling via intracellular Ca(2+) levels (Probable). Besides, mediates the release of lysosomal Zn(2+) stores in response to reactive oxygen species, leading to increased cytosolic Zn(2+) levels (PubMed:25562606, PubMed:27068538). Activated by moderate heat (35 to 40 degrees Celsius) (PubMed:16601673). Activated by intracellular ADP-ribose, beta-NAD (NAD(+)) and similar compounds, and by oxidative stress caused by reactive oxygen or nitrogen species (PubMed:11960981, PubMed:11385575, PubMed:11509734, PubMed:11804595, PubMed:15561722, PubMed:16601673, PubMed:19171771, PubMed:27383051, PubMed:27068538). The precise physiological activators are under debate; the true, physiological activators may be ADP-ribose and ADP-ribose-2'-phosphate (PubMed:20650899, PubMed:25918360). Activation by ADP-ribose and beta-NAD is strongly increased by moderate heat (35 to 40 degrees Celsius) (PubMed:16601673). Likewise, reactive oxygen species lower the threshold for activation by moderate heat (37 degrees Celsius) (PubMed:22493272). Plays a role in mediating behavorial and physiological responses to moderate heat and thereby contributes to body temperature homeostasis. Plays a role in insulin secretion, a process that requires increased cytoplasmic Ca(2+) levels (By similarity). Required for normal IFNG and cytokine secretion and normal innate immune immunity in response to bacterial infection. Required for normal phagocytosis and cytokine release by macrophages exposed to zymosan (in vitro). Plays a role in dendritic cell differentiation and maturation, and in dendritic cell chemotaxis via its role in regulating cytoplasmic Ca(2+) levels (By similarity). Plays a role in the regulation of the reorganization of the actin cytoskeleton and filopodia formation in response to reactive oxygen species via its role in increasing cytoplasmic Ca(2+) and Zn(2+) levels (PubMed:27068538). Confers susceptibility to cell death following oxidative stress (PubMed:12594222, PubMed:25562606).[UniProtKB:Q91YD4] Isoform 2: Lacks cation channel activity. Does not mediate cation transport in response to oxidative stress or ADP-ribose. Isoform 3: Lacks cation channel activity and negatively regulates the channel activity of isoform 1. Negatively regulates susceptibility to cell death in reposponse to oxidative stress. Publication Abstract from PubMed Transient receptor potential (TRP) melastatin 2 (TRPM2) is a cation channel associated with numerous diseases. It has a C-terminal NUDT9 homology (NUDT9H) domain responsible for binding ADP-ribose (ADPR), and both ADPR and Ca(2+) are required for TRPM2 activation. Here we report cryo-EM structures of human TRPM2, alone, with ADPR, and with ADPR and Ca(2+) NUDT9H forms both intra- and inter-subunit interactions with the N-terminal TRPM homology region (MHR1/2/3) in the apo state, but undergoes conformational changes upon ADPR binding, resulting in rotation of MHR1/2 and disruption of the inter-subunit interaction. Ca(2+) binding further engages transmembrane helices and the conserved TRP helix to cause conformational changes at the MHR arm and the lower gating pore to potentiate channel opening. These findings explain the molecular mechanism of concerted TRPM2 gating by ADPR and Ca(2+) and provide insights into the gating mechanism of other TRP channels. Structures and gating mechanism of human TRPM2.,Wang L, Fu TM, Zhou Y, Xia S, Greka A, Wu H Science. 2018 Nov 22. pii: science.aav4809. doi: 10.1126/science.aav4809. PMID:30467180 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.