DRiP78分子调控HIV-1感染和复制的机制研究

Dopamine receptor interactng protein 78 (DRiP78) acts as a important regulator involved in signaling and transportation of G protein-coupled receptors (GPCRs). Chemokine receptors are members of the GPCRs family. CCR5 and CXCR4 act as coreceptors for human immunodeficiency virus type I (HIV-1) and several efforts have been made to develop ligands to inhibit HIV infection by blocking those receptors. Removal of chemokine receptors from cell surface via polymorphism or other means confers some levels of immunity against HIV infection. However, very limited successes have been obtained via ligand therapy so we explore potential avenues to regulate chemokine receptor expression at the plasma membrane. We identified a molecular chaperone, DRiP78, that interacts with both CXCR4 and CCR5 homodimers,but not the heterodimer formed by those receptors. We identified the interaction region on the receptor, the F(x)6LL motif, and show that upon mutation of this motif the chaperone cannot interact with the receptor. DRiP78 is involved in the assembly of CCR5 chemokine signaling complex as a homodimer, as well as with the Gαi protein. Finally, we show that modulation of DRiP78 levels will affect receptor functions, such as cell migration. Our results demonstrate that modulation of the functions of a chaperone can affect signal transduction at the cell surface.Here,in this proposal,based on our previous work,we are seeking to understand the effects of DRiP78 on CXCR4 and CCR5 HIV-1 infection and replication.In addition, the mechanism by which the roles of DRiP78 on HIV-1 will also be dissected, including the effects of DRiP78 on HIV-1 induced host cell signal cascades activation,the rearrangement of cytoskeleton filamentous actin etc.The proposed project will reveal the mechanism of DRiP78 on HIV-1 infection and replication, as well as pay the way for development of novel anti-HIV-1 drugs based on the coreceptors-interacting molecules.

DRiP78是调控G蛋白偶联受体信号转导和胞内运输的一个重要分子。我们前期研究证明，DRiP78可以结合趋化因子受体CXCR4或CCR5的同源二聚体,并参与G蛋白复合物的信号组装,以及调节受体介导的下游生物学功能。CXCR和CCR5是HIV-1的重要辅助受体。但是，DRiP78蛋白对CXCR/CCR5介导的HIV-1病毒的感染和复制目前尚无研究。我们拟对DRiP78分子在CXCR4和CCR5配体诱导的受体内化，介导的HIV-1感染宿主细胞后，病毒的进入、胞内复制和病毒的产生等方面进行研究，明确DRiP78分子在不同受体介导的感染中的作用；同时，对HIV-1共受体介导的、病毒感染激活的相关宿主细胞信号途径进行分析，阐明其在HIV-1感染复制过程中的调控机制，为基于DRiP78等共受体调控分子的新型抗病毒药物的开发奠定基础。

DRiP78是调控G蛋白偶联受体信号转导和胞内运输的一个重要分子。我们前期研究证明，DRiP78 可以结合趋化因子受体CXCR4或CCR5的同源二聚体,并参与G蛋白复合物的信号组装,以及调节受体介导的下游生物学功能。CXCR4和CCR5是HIV-1的重要辅助受体。但是，DRiP78蛋白对CXCR/CCR5介导的HIV-1病毒的感染和复制目前尚无研究。我们拟对DRiP78分子在CXCR4和CCR5配体诱导的受体内化，介导的HIV-1感染宿主细胞后，病毒的进入、胞内复制和病毒的产生等方面进行研究，明确DRiP78分子在不同受体介导的感染中的作用；同时，对HIV-1共受体介导的、病毒感染激活的相关宿主细胞信号途径进行分析。在本项目中，我们研究发现，DRiP78增加了CXCR4在细胞质膜上的表达，但是抑制了CCR5在细胞质膜上的表达。在DRiP78稳定敲减的GHOST(3)-CD4-CXCR4细胞内，DRiP78特异性shRNA可以限制CXCR4嗜性的HIV-1病毒的复制，DRiP78下调了HIV-1诱导的MAPK/Erk和cofilin的磷酸化，但对FAK的磷酸化没有明显影响。DRiP78在HIV-1逆转录后、PIC复合物转核和整合之前的的阶段调控病毒的复制。本研究项目阐明了DRiP78分子在HIV-1感染复制过程中的调控机制，为基于DRiP78 等共受体调控分子的新型抗病毒药物的开发奠定了基础。