Structure, inhibition and regulation of two-pore channel TPC1 from Arabidopsis thaliana.
Structure, inhibition and regulation of two-pore channel TPC1 from Arabidopsis thaliana.
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DOI：
10.1038/nature17194
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发表时间：
2016-03-10
期刊：
影响因子：
64.8
通讯作者：
Stroud RM
中科院分区：
文献类型：
--
作者：
Kintzer AF;Stroud RM
双孔通道（TPC）包括真核生物电压门控和配体门控阳离子通道的一个亚家族（TPC 1 -3），具有两个非等同的串联孔形成亚基，其二聚化形成准四聚体。在液泡膜或内溶酶体膜中发现，它们调节钠和钙离子的传导、囊泡内pH、运输和兴奋性。TPC通过跨膜电位降低和胞浆钙浓度增加而激活，受到低管腔pH和钙的抑制，并受磷酸化调节。在这里，我们报告了2.87 nm分辨率的拟南芥TPC 1的晶体结构，作为理解离子渗透、通道激活、电压敏感域的位置和调节离子结合位点的基础。我们确定了磷酸化的位点，在氨基末端和羧基末端的结构域被定位为变构调节胞质Ca 2+激活。两个电压敏感结构域之一（VSD 2）编码电压敏感性和抑制管腔Ca 2+，并采用不同于其他电压门控离子通道结构中观察到的激活状态的构象。该结构表明，有效的药效团trans-Ned-19（参考文献）通过将孔结构域夹在VSD 2上而发挥变构作用。在动物中，Ned-19预防埃博拉病毒和其他丝状病毒的感染，可能是通过改变它们与内溶酶体的融合并将其内容物输送到细胞质中。
Two-pore channels (TPCs) comprise a subfamily (TPC1–3) of eukaryotic voltage- and ligand-gated cation channels,with two non-equivalent tandem pore-forming subunits that 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,,,and an increase in cytosolic calcium concentrations,, are inhibited by low luminal pH and calcium, and are regulated by phosphorylation,. Here we report the crystal structure of TPC1 fromArabidopsis thalianaat 2.87 Å 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 amino-terminal and carboxy-terminal domains that are positioned to allosterically modulate cytoplasmic Ca2+activation. One of the two voltage-sensing domains (VSD2) encodes voltage sensitivity and inhibition by luminal Ca2+and adopts a conformation distinct from the activated state observed in structures of other voltage-gated ion channels,. The structure shows that potent pharmacophoretrans-Ned-19 (ref. ) acts allosterically by clamping the pore domains to VSD2. In animals, Ned-19 prevents infection by Ebola virus and other filoviruses, presumably by altering their fusion with the endolysosome and delivery of their contents into the cytoplasm.