Tangier disease is caused by mutations in ATP binding cassette transporter A1( ABCA1). ABCA1 interacts with lipid-free apolip oproteins, promoting phospholipid and cholesterol efflux from cells and giving r ise to HDL...Tangier disease is caused by mutations in ATP binding cassette transporter A1( ABCA1). ABCA1 interacts with lipid-free apolip oproteins, promoting phospholipid and cholesterol efflux from cells and giving r ise to HDL particles. ABCA1 may act as a phospholipid translocase facilitating p hospholipid binding to apoA-I. ABCA1 gene expression is upregulated in cholester ol-loaded cells as a result of activation of LXR/RXR-mediated gene transcription . LXR and RXR coordinately induce a battery of genes mediating cellular choleste rol efflux, centripetal cholesterol transport, and cholesterol excretion in bile . Small-molecule activators of LXR/RXR or other stimulators of macrophage or int estinal cholesterol efflux hold great promise as future treatments for atheroscl erosis.展开更多
目的:研究微小RNA(microRNA,miR)-218-5p靶向调控三磷酸腺苷结合盒超家族G家族第2个成员(ATP-binding cassette sub-family G member 2,ABCG2)基因对Tca-8113细胞的增殖、迁移和侵袭的影响,并探讨其机制。方法:运用实时荧光定量聚合酶...目的:研究微小RNA(microRNA,miR)-218-5p靶向调控三磷酸腺苷结合盒超家族G家族第2个成员(ATP-binding cassette sub-family G member 2,ABCG2)基因对Tca-8113细胞的增殖、迁移和侵袭的影响,并探讨其机制。方法:运用实时荧光定量聚合酶链反应(quantitative Real-time PCR,qRT-PCR)与Western blot检测Tca-8113细胞和NOK细胞中miR-218-5p和ABCG2的表达。通过双荧光素酶报告基因实验检测miR-218-5p和ABCG2靶向关系。用脂质体法将miR-218-5p mimic、ABCG2小干扰RNA(interfering RNA,siRNA)、miR-218-5p mimic+pcDNA-ABCG2分别转染至Tca-8113细胞中,噻唑蓝(methyl thiazol tetrazolium,MTT)法、Transwell法检测Tca-8113细胞的增殖、迁移和侵袭。结果:与NOK细胞比较,Tca-8113细胞miR-218-5p呈显著低表达,ABCG2呈显著高表达(P<0.05)。过表达miR-218-5p、抑制ABCG2均可抑制Tca-8113细胞的增殖和迁移(P<0.05)。双荧光素酶报告基因实验证实miR-218-5p与ABCG2的靶向结合关系。过表达ABCG2可逆转上调miR-218-5p对Tca-8113细胞增殖、迁移和侵袭的抑制作用。结论:上调miR-218-5p的表达可靶向调控ABCG2,抑制Tca-8113细胞的增殖、迁移和侵袭,将可为口腔鳞状细胞癌的治疗提供新的靶点。展开更多
三磷酸腺苷结合盒式(ATP-binding cassette,ABC)输出转运体是一类典型的蛋白质分子机器,这类分子机器通过门控运动进行“向外打开”(outward-facing,OF)和“向内打开”(inward-facing,IF)构象态之间转换,从而把底物转运输出生物膜外。...三磷酸腺苷结合盒式(ATP-binding cassette,ABC)输出转运体是一类典型的蛋白质分子机器,这类分子机器通过门控运动进行“向外打开”(outward-facing,OF)和“向内打开”(inward-facing,IF)构象态之间转换,从而把底物转运输出生物膜外。尽管结构和功能的研究已取得重大进展,但对ABC输出转运体构象门控的分子机制还没有完全理解。由于全原子分子动力学存在长时间尺度问题,因此对ABC蛋白质分子构象变化不能进行完全描述。本文应用粗粒化分子动力学(CG-MD)结合改善的抽样方法,对细菌ABC输出转运体MsbA进行计算模拟研究。本文计算得到的平均力势(potential of mean force,PMF)表明,从OF构象态到IF构象态之间的转变需要经过一个“阻塞态”(occluded state,OC),即MsbA的内门和外门都是关闭的状态。这种阻塞状态对ABC输出功能的方向单一性具有重要意义。我们的CG-MD计算模拟结果显示,随着MsbA的核苷酸结合域(nucleotide binding domain,NBD)的分离,外门的关闭和内门的打开是采用高度协作的方式。基于本文的计算模拟结果,我们提出了一个与目前文献中发表的有很大不同的机械力学模型,揭示了ABC输出转运体通过构象门控运动输运底物的分子机制。展开更多
文摘Tangier disease is caused by mutations in ATP binding cassette transporter A1( ABCA1). ABCA1 interacts with lipid-free apolip oproteins, promoting phospholipid and cholesterol efflux from cells and giving r ise to HDL particles. ABCA1 may act as a phospholipid translocase facilitating p hospholipid binding to apoA-I. ABCA1 gene expression is upregulated in cholester ol-loaded cells as a result of activation of LXR/RXR-mediated gene transcription . LXR and RXR coordinately induce a battery of genes mediating cellular choleste rol efflux, centripetal cholesterol transport, and cholesterol excretion in bile . Small-molecule activators of LXR/RXR or other stimulators of macrophage or int estinal cholesterol efflux hold great promise as future treatments for atheroscl erosis.
基金supported by the National Natural Science Foundation of China(21073170,21273209).
文摘三磷酸腺苷结合盒式(ATP-binding cassette,ABC)输出转运体是一类典型的蛋白质分子机器,这类分子机器通过门控运动进行“向外打开”(outward-facing,OF)和“向内打开”(inward-facing,IF)构象态之间转换,从而把底物转运输出生物膜外。尽管结构和功能的研究已取得重大进展,但对ABC输出转运体构象门控的分子机制还没有完全理解。由于全原子分子动力学存在长时间尺度问题,因此对ABC蛋白质分子构象变化不能进行完全描述。本文应用粗粒化分子动力学(CG-MD)结合改善的抽样方法,对细菌ABC输出转运体MsbA进行计算模拟研究。本文计算得到的平均力势(potential of mean force,PMF)表明,从OF构象态到IF构象态之间的转变需要经过一个“阻塞态”(occluded state,OC),即MsbA的内门和外门都是关闭的状态。这种阻塞状态对ABC输出功能的方向单一性具有重要意义。我们的CG-MD计算模拟结果显示,随着MsbA的核苷酸结合域(nucleotide binding domain,NBD)的分离,外门的关闭和内门的打开是采用高度协作的方式。基于本文的计算模拟结果,我们提出了一个与目前文献中发表的有很大不同的机械力学模型,揭示了ABC输出转运体通过构象门控运动输运底物的分子机制。
