Lu Yanning, Liu Ding Xiang, Tam James P
School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
Biochem Biophys Res Commun. 2008 May 2;369(2):344-9. doi: 10.1016/j.bbrc.2008.02.023. Epub 2008 Feb 13.
Lipid rafts often serve as an entry site for certain viruses. Here, we report that lipid rafts in Vero E6 cells are involved in the entry of severe acute respiratory syndrome coronavirus (SARS-CoV). Infectivity assay showed the integrity of lipid rafts was required for productive infection of pseudotyped SARS-CoV. Depletion of plasma membrane cholesterol with MbetaCD relocalized raft-resident marker caveolin-1 as well as SARS-CoV receptor ACE2 to a nonraft environment, but did not significantly change the surface expression of ACE2. MbetaCD-treatment inhibited infectivity of pseudotyped SARS-CoV by 90%. Biochemical fractionation and confocal imaging confirmed that ACE2 colocalized with raft-resident markers. Furthermore, an ectodomain of SARS-CoV S protein (S1188HA) could associate with lipid rafts after binding to its receptor, and colocalize with raft-resident marker ganglioside GM1. The binding of S1188HA was not affected by depleting plasma membrane cholesterol. Taken together, our results support that lipid rafts serve as an entry port for SARS-CoV.
脂筏常常充当某些病毒的进入位点。在此,我们报告Vero E6细胞中的脂筏参与严重急性呼吸综合征冠状病毒(SARS-CoV)的进入过程。感染性测定表明,有生产性的假型SARS-CoV感染需要脂筏的完整性。用甲基-β-环糊精(MbetaCD)消耗质膜胆固醇会使脂筏驻留标记小窝蛋白-1以及SARS-CoV受体血管紧张素转换酶2(ACE2)重新定位到非脂筏环境中,但并未显著改变ACE2的表面表达。MbetaCD处理使假型SARS-CoV的感染性降低了90%。生化分级分离和共聚焦成像证实ACE2与脂筏驻留标记物共定位。此外,SARS-CoV S蛋白的胞外域(S1188HA)在与其受体结合后可与脂筏结合,并与脂筏驻留标记物神经节苷脂GM1共定位。S1188HA的结合不受质膜胆固醇消耗的影响。综上所述,我们的结果支持脂筏充当SARS-CoV的进入端口。