Department of Life Science, Tunghai University, Taichung, Taiwan, ROC.
Biochem Biophys Res Commun. 2011 Oct 22;414(2):337-43. doi: 10.1016/j.bbrc.2011.09.070. Epub 2011 Sep 17.
Our previous study shows that caveolin-1 colocalizes and interacts with ATP-binding cassette transporter A1 (ABCA1), which is intimately involved in cellular cholesterol efflux. In this study, we further clarified the region of caveolin-1 that interacts with ABCA1. We also examined the interaction between mutant caveolin-1 and ABCA1 in HDL-mediated cholesterol efflux. We constructed a panel of mutant caveolin-1 proteins and co-transfected them into rat aortic endothelial and human embryonic kidney 293 (HEK293) cells. The co-immunoprecipitation shows that mutant oligomerization domain of caveolin-1, caveolin-1(Δ62-100), is required for the interaction of caveolin-1 with ABCA1. Caveolin-1(Δ62-100) did not colocalize with ABCA1 in the cholesterol-loaded cells after HDL incubation as observed by immunofluorescence confocal microscopy. Concomitantly, caveolin-1(Δ62-100) suppressed HDL-mediated cholesterol efflux. The results suggest that the region of caveolin-1 between amino acids 62 and 100 is an oligomerization domain as well as an attachment site for ABCA1 interaction that regulates HDL-mediated cholesterol efflux.
我们之前的研究表明，窖蛋白-1 与三磷酸腺苷结合盒转运体 A1（ABCA1）共定位并相互作用，ABCA1 与细胞胆固醇外流密切相关。在这项研究中，我们进一步阐明了窖蛋白-1 与 ABCA1 相互作用的区域。我们还研究了突变窖蛋白-1 和 HDL 介导的胆固醇外流过程中 ABCA1 之间的相互作用。我们构建了一组突变窖蛋白-1 蛋白，并将其共转染到大鼠主动脉内皮细胞和人胚肾 293（HEK293）细胞中。共免疫沉淀表明，突变寡聚化结构域的窖蛋白-1（Δ62-100）是窖蛋白-1 与 ABCA1 相互作用所必需的。免疫荧光共聚焦显微镜观察到，胆固醇负载细胞孵育 HDL 后，突变的窖蛋白-1（Δ62-100）与 ABCA1 不再共定位。同时，窖蛋白-1（Δ62-100）抑制了 HDL 介导的胆固醇外流。结果表明，氨基酸 62 到 100 之间的窖蛋白-1 区域既是一个寡聚化结构域，也是与 ABCA1 相互作用的附着位点，调节 HDL 介导的胆固醇外流。
