Thapsigargin inhibits the sarcoplasmic or endoplasmic reticulum Ca-ATPase family of calcium pumps.
Thapsigargin inhibits the sarcoplasmic or endoplasmic reticulum Ca-ATPase family of calcium pumps.
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DOI：
10.1016/s0021-9258(19)47340-7
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发表时间：
1991-09
期刊：
影响因子：
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通讯作者：
Jonathan LyttonSg;Marisa WestlinS;Michael R. Hanleyll
中科院分区：
文献类型：
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作者：
Jonathan LyttonSg;Marisa WestlinS;Michael R. Hanleyll
ATP依赖的钙摄取进入细胞内储存室的作用是神经诱导的钙信号传导的基本特征。毒胡萝卜素，一种非phorboid肿瘤促进剂，越来越多地被用于操纵钙储存，因为它诱导细胞溶质钙的类钙离子升高。已经表明毒胡萝卜素通过抑制内质网钙泵起作用。我们已经直接测试了毒胡萝卜素对所有已知的细胞内型钙泵（称为肌质或内质网Ca-ATP酶家族（SERCA））的特异性。全长cDNA克隆编码SERCA 1，SERCA 2a，SERCA 2b，和SERCA 3酶在COS细胞中表达，和钙摄取和钙依赖性ATP酶活性测定从他们分离的微粒体。毒胡萝卜素抑制所有的SERCA同工酶具有相同的效力。同样剂量的毒胡萝卜素可抑制快收缩肌和心肌肌浆网的钙摄取和ATP酶活性，但对质膜Ca-ATP酶和Na，K-ATP酶均无影响。毒胡萝卜素与SERCA亚型的相互作用是快速的、化学计量的且基本上不可逆的。这些性质表明毒胡萝卜素与识别位点相互作用，该识别位点存在于且仅存在于内质网和肌浆网钙泵家族的所有成员中。
The role of ATP-dependent calcium uptake into intracellular storage compartments is an essential feature of hormonally induced calcium signaling. Thapsigargin, a non-phorboid tumor promoter, increasingly is being used to manipulate calcium stores because it induces a hormone-like elevation of cytosolic calcium. It has been suggested that thapsigargin acts through inhibition of the endoplasmic reticulum calcium pump. We have directly tested the specificity of thapsigargin on all of the known intracellular-type calcium pumps (referred to as the sarcoplasmic or endoplasmic reticulum Ca-ATPase family (SERCA]. Full-length cDNA clones encoding SERCA1, SERCA2a, SERCA2b, and SERCA3 enzymes were expressed in COS cells, and both calcium uptake and calcium-dependent ATPase activity were assayed in microsomes isolated from them. Thapsigargin inhibited all of the SERCA isozymes with equal potency. Furthermore, similar doses of thapsigargin abolished the calcium uptake and ATPase activity of sarcoplasmic reticulum isolated from fast twitch and cardiac muscle but had no influence on either the plasma membrane Ca-ATPase or Na,K-ATPase. The interaction of thapsigargin with the SERCA isoforms is rapid, stoichiometric, and essentially irreversible. These properties demonstrate that thapsigargin interacts with a recognition site found in, and only in, all members of the endoplasmic and sarcoplasmic reticulum calcium pump family.