Thapsigargin or curcumin does not promote maturation of processing mutants of the ABC transporters, CFTR, and P-glycoprotein
Thapsigargin or curcumin does not promote maturation of processing mutants of the ABC transporters, CFTR, and P-glycoprotein
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DOI：
10.1016/j.bbrc.2004.10.070
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发表时间：
2004-12-10
影响因子：
3.1
通讯作者：
Clarke, DM
中科院分区：
文献类型：
--
作者：
Loo, TW;Bartlett, MC;Clarke, DM
CFTR和P-糖蛋白（P-gp）的质膜蛋白被分子伴侣保留在内质网（ER）中。通过SERCA钙泵抑制剂毒胡萝卜素或姜黄素消耗ER中的钙储存抑制了这些相互作用，并允许蛋白质运输到质膜[Nat.Med.8（2002）485; Science 304（2004）600]。我们通过用毒胡萝卜素或姜黄素处理表达CFTR或P-gp的错误加工突变体的各种细胞系来测试这一假设。通过全细胞提取物的免疫印迹分析检测未成熟核心糖基化蛋白向成熟产物的转化。在任何错误加工的突变体中均未检测到成熟产物。相比之下，所有错误处理的P-gp突变体被化学伴侣/药物底物环孢菌素A以剂量依赖性方式拯救。这些结果表明毒胡萝卜素或姜黄素在挽救P-gp和CFTR的错误加工突变体中无效，（C）2004 Elsevier Inc. All rights reserved.
Misprocessed plasma membrane proteins of CFTR and P-glycoprotein (P-gp) are retained in the endoplasmic reticulum (ER) by molecular chaperones. Depletion of the calcium stores in the ER by the SERCA calcium pump inhibitors thapsigargin or curcumin inhibits these interactions and allows the protein to be trafficked to the plasma membrane [Nat. Med. 8 (2002) 485; Science 304 (2004) 600]. We tested this hypothesis by treating various cell lines expressing misprocessed mutants of CFTR or P-gp with thapsigargin or curcumin. Conversion of the immature core-glycosylated protein to mature product was detected by immunoblot analysis of whole cell extracts. Mature product was not detected in any of the misprocessed mutants. By contrast, all misprocessed P-gp mutants were rescued by the chemical chaperone/drug substrate cyclosporin A in a dose-dependent manner. These results show that thapsigargin or curcumin is not effective in rescuing misprocessed mutants of P-gp and CFTR, (C) 2004 Elsevier Inc. All rights reserved.