scholarly journals Structure, inhibition and regulation of two-pore channel TPC1 from Arabidopsis thaliana

Nature ◽  
2016 ◽  
Vol 531 (7593) ◽  
pp. 258-264 ◽  
Author(s):  
Alexander F. Kintzer ◽  
Robert M. Stroud
2017 ◽  
Author(s):  
Alexander F. Kintzer ◽  
Robert M. Stroud

AbstractIn eukaryotes, two-pore channels (TPC1-3) comprise a family of ion channels that regulate the conductance of Na+ and Ca2+ ions across cellular membranes. TPC1-3 form endolysosomal channels, but TPC3 can also function in the plasma membrane. TPC1/3 are voltage-gated channels, but TPC2 opens in response to binding endolysosome-specific lipid phosphatidylinositol-3,5-diphosphate (PI(3,5)P2). Filoviruses, such as Ebola, exploit TPC-mediated ion release as a means of escape from the endolysosome during infection. Antagonists that block TPC1/2 channel conductance abrogate filoviral infections. TPC1/2 form complexes with the mechanistic target of rapamycin complex 1 (mTORC1) at the endolysosomal surface that couple cellular metabolic state and cytosolic nutrient concentrations to the control of membrane potential and pH. We determined the X-ray structure of TPC1 from Arabidopsis thaliana (AtTPC1) to 2.87Å resolution–one of the two first reports of a TPC channel structure. Here we summarize these findings and the implications that the structure may have for understanding endolysosomal control mechanisms and their role in human health.AbbreviationsmTORC1Mechanistic target of rapamycin complex 1TPCTwo-pore channelPI(3,5)P2Phosphatidylinositol-3,5-diphosphateAtTPC1Arabidopsis thaliana TPC1NED19Trans-Ned-19VSDVoltage-sensing domainP1Pore domain in S5-S6P2Pore domain in S11-S12CavVoltage-gated calcium channelNavVoltage-gated sodium channelKvVoltage-gated potassium channelNTDN-terminal domainCTDC-terminal domainEFEF-hand domainNAADPNicotinic acid adenine dinucleotide phosphatePI(4,5)P2Phosphatidylinositol-4,5-diphosphateDHPDihydropyridinePAAPhenylalkylamineBTZBenzothiazepineCaa2+Activating Ca2+-ionCai2+Inhibitory Ca2+-ionfou2Fatty acid oxygenation up-regulated 2SLC38a9Sodium-coupled neutral amino acid transporter 9NPC1Niemann-Pick C1PKAProtein kinase APKCProtein kinase CPKGProtein kinase GH+ATPase - Proton Pump32P– Phosphorus-32


Nature ◽  
2015 ◽  
Vol 531 (7593) ◽  
pp. 196-201 ◽  
Author(s):  
Jiangtao Guo ◽  
Weizhong Zeng ◽  
Qingfeng Chen ◽  
Changkeun Lee ◽  
Liping Chen ◽  
...  

2016 ◽  
Author(s):  
Alexander F Kintzer ◽  
Robert M Stroud

Two-pore channels (TPCs) comprise a subfamily (TPC1-3) of eukaryotic voltage- and ligand-gated cation channels that contain two non-equivalent tandem pore-forming subunits that then dimerize to form quasi-tetramers. Found in vacuolar or endolysosomal membranes, they regulate the conductance of sodium and calcium ions, intravesicular pH, trafficking and excitability. TPCs are activated by a decrease in transmembrane potential, an increase in cytosolic calcium concentrations, and inhibited by luminal low pH, and calcium, and regulated by phosphorylation,. We report the crystal structure of TPC1 from Arabidopsis thaliana (TPC1) at 2.8x4.0x3.3 angstrom resolution as a basis for understanding ion permeation, channel activation, the location of voltage-sensing domains, and regulatory ion-binding sites. We determined sites of phosphorylation in the N-terminal and C-terminal domains that are positioned to allosterically modulate cytoplasmic Ca2+-activation. One of the two voltage sensing domains (VSDII) encodes voltage sensitivity and inhibition by lumenal Ca2+ and adopts a conformation distinct from the activated state observed in structures of other voltage-gated ion channels. The structure shows that potent pharmacophore trans-NED19 allosterically acts by clamping the pore domains to VSDII. In animals NED19 prevents infection by Ebola virus and Filoviruses presumably by altering their fusion with the endolysosome, and delivery of their contents into the cytoplasm.


1994 ◽  
Vol 5 (4) ◽  
pp. 551-558 ◽  
Author(s):  
Seok So Chang ◽  
Soon Ki Park ◽  
Byung Chul Kim ◽  
Bong Joong Kang ◽  
Dal Ung Kim ◽  
...  

1995 ◽  
Vol 95 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Maarten Koornneef ◽  
Corrie Hanhart ◽  
Patty van Loenen-Martinet ◽  
Hetty Blankestijn de Vries

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