Elucidating the Structural Bases of HIV-1-Induced CD4 Degradation

阐明 HIV-1 诱导的 CD4 降解的结构基础

• 批准号: 10698255
• 负责人: XIAOFEI JIA
• 金额: $ 53.13万
• 依托单位: UNIVERSITY OF MASSACHUSETTS DARTMOUTH
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10698255
• 关键词: Affinity; Anti-Retroviral Agents; Back; Binding; Biochemical; CD4 Antigens; CD4 Positive T Lymphocytes; Cell surface; Cells; Chemicals; Clathrin; Clathrin Adaptors; Complex; Cryoelectron Microscopy; Crystallography; Cullin Proteins; Cytoplasmic Tail; Data; Degradation Pathway; Development; Down-Regulation; Drug resistance; Endocytosis; Endoplasmic Reticulum; Endosomes; Event; Excision; HIV; HIV Infections; HIV Receptors; HIV-1; Human; Immune; Immune response; In Vitro; Individual; Infection; Integration Host Factors; Knowledge; Laboratories; Literature; Lysosomes; Mediating; Molecular; Multivesicular Body; Pathway interactions; Pharmaceutical Preparations; Play; Polyubiquitination; Proteins; Resolution; Role; Secure; Series; Structure; Substrate Interaction; Surface; Testing; Therapeutic; Transcription Factor AP-1; Variant; Vesicle; Viral; Viral Proteins; Virion; Virus; Virus Inhibitors; Virus Replication; Work; antiretroviral therapy; base; beta-Transducin Repeat-Containing Proteins; combat; crosslink; design; drug discovery; enhancer-binding protein AP-2; experience; immune clearance; improved; inhibitor; insight; molecular assembly/self assembly; multicatalytic endopeptidase complex; nef Protein; novel; novel therapeutics; protein transport; recruit; side effect; trafficking; trans-Golgi Network; ubiquitin-protein ligase; viral rebound; vpu Protein

PROJECT SUMMARY: Currently available antiretroviral therapy is effective in treating HIV infection but cannot eliminate it. Once treat- ment is stopped, viral rebound typically occurs within weeks. Infected individuals must take antiretroviral drugs throughout their lives and, as a consequence, may experience drug resistance and side effects. Novel antiretro- virals that can better treat or even eliminate HIV infection are highly desired. One promising and yet underap- preciated approach is to develop therapeutics that disrupt HIV-induced downregulation of the CD4 receptor and thereby unleash CD4’s remarkable inhibitory power to combat the infection. CD4 is the entry receptor for HIV and plays a vital role in the initial stage of the infection, but its presence later in the virus’ replication cycle strongly inhibits viral replication and sensitizes infected cells to immune-clearance. The potency of CD4 as an inhibitor of the virus is reflected by the stringent, highly concerted mechanisms HIV uses to antagonize CD4. Two viral proteins, Nef and Vpu, are involved in downregulating CD4 from the cell surface and from the endoplasmic reticulum, respectively, leading to degradation of CD4 in either the lysosome (Nef-mediated pathway) or the proteasome (Vpu-mediated pathway). The level of effort here by HIV is arguably unmatched—no other host factors including the well-known restriction factors are antagonized in such a multifaceted manner. This suggests that restoring CD4 levels in infected cells may be significantly damaging to the virus and significantly beneficial to the host. Designing or developing therapeutics to restore CD4 levels, however, is greatly hindered by the lack of high-resolution structural information on the pertinent molecular assemblies, e.g., how Nef and Vpu each recruit CD4 into hijacked host trafficking and degradation machineries. In this project, we will solve such high- resolution structures to gain the knowledge necessary for this drug discovery approach. Our specific aims are: 1) Elucidate how the viral Nef protein hijacks the clathrin adaptor protein AP1 to enable the retention of CD4 in endosomes, thus facilitating the delivery of CD4 to lysosomes for degradation. 2) Reveal how Nef hijacks the host trafficking protein ALIX to channel CD4 into multivesicular bodies and lysosomes for degradation; investigate whether and, if so how, the ALIX-like protein PTPN23 participates in Nef-mediated degradation of CD4 and/or other host factors. 3) Elucidate how the viral Vpu protein targets newly synthesized CD4 in the ER to mediate its polyubiquiti- nation via the β-TrCP/cullin1 complex, thereby redirecting CD4 to the proteasome for degradation. Successful completion of this work should reveal opportunities for the design and/or development of novel ther- apeutics capable of disrupting HIV-induced CD4 degradation, thus restoring CD4 in infected cells to inhibit HIV replication or even eliminate the infection.

项目总结： 目前可用的抗逆转录病毒疗法在治疗艾滋病毒感染方面有效，但不能消除它。一次治疗- 如果病毒感染停止，病毒反弹通常会在几周内发生。感染者必须服用抗逆转录病毒药物 在他们的一生中，可能会出现抗药性和副作用。新的反复古- 人们非常希望能更好地治疗甚至消除艾滋病毒感染的病毒。有一个很有希望但却很不足的- 最好的方法是开发治疗方法，阻断艾滋病毒诱导的CD4受体下调和 从而释放CD_4‘S显着的抗感染抑制能力。CD4是HIV的进入受体 在感染的初始阶段起着至关重要的作用，但在病毒复制周期的后期它的存在是强有力的 抑制病毒复制，并使感染细胞对免疫清除敏感。CD_4作为一种血管紧张素转换酶抑制剂的效力 这种病毒反映在HIV用来对抗CD4的严格、高度协调的机制上。两个病毒式的 蛋白质Nef和VPu参与从细胞表面和内质向下调节cd4。 分别导致溶酶体(Nef介导的途径)或 蛋白酶体(VPU介导的途径)。艾滋病毒在这里所做的努力可以说是无与伦比的--没有其他宿主 包括众所周知的限制因素在内的因素以这样一种多方面的方式被对抗。这表明 恢复受感染细胞中的CD4水平可能会对病毒造成重大损害，并显著受益 敬东道主。然而，设计或开发恢复cd4水平的疗法很大程度上受到了缺乏的阻碍。 有关分子组件的高分辨率结构信息，例如Nef和VPu各自如何 招募CD4到被劫持的宿主贩运和降解机器中。在这个项目中，我们将解决这样的高- 拆分结构，以获得这种药物发现方法所需的知识。我们的具体目标是： 1)阐明病毒Nef蛋白如何劫持笼状蛋白接头蛋白AP1以使CD4滞留 在内小体中，从而促进将CD4运送到溶酶体进行降解。 2)揭示Nef如何劫持宿主运输蛋白Alix，将CD4引导到多囊体中，并 溶酶体参与降解；研究Alix样蛋白PTPN23是否参与，如果参与，如何参与 在Nef介导的CD4和/或其他宿主因素的降解中。 3)阐明病毒VPU蛋白是如何靶向内质网中新合成的CD4来调节其多泛性的。 通过β-TrCP/CULIN1复合体，从而将CD4重定向到蛋白酶体进行降解。 这项工作的成功完成将为设计和/或开发新型热泵提供机会。 能够破坏HIV诱导的CD4降解的调理药物，从而恢复感染细胞中的CD4以抑制HIV 复制甚至消除感染。