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.

项目摘要： 目前可用的抗逆转录病毒疗法可有效治疗HIV感染，但无法消除。一旦治疗 孟停下来，病毒反弹通常发生在数周之内。受感染的人必须服用抗逆转录病毒药物 在他们的生活中，因此可能会遇到耐药性和副作用。新颖的抗逆性 高度需要更好地治疗甚至消除HIV感染的病毒。一个诺言，但不足 先进的方法是开发破坏艾滋病毒诱导的CD4接收器下调的治疗和 从而释放了CD4的显着抑制能力，可以抵抗感染。 CD4是HIV的入口受体 并在感染的初始阶段起着至关重要的作用，但后来在病毒复制周期中存在很强的作用 抑制病毒复制，并感知被感染的细胞对免疫清除率。 CD4作为抑制剂的效力 该病毒反映出HIV用来对抗CD4的严格，高度协调的机制。两个病毒 蛋白质，Nef和VPU参与了从细胞表面和内质的下调CD4 网状分别导致CD4在溶酶体（NEF介导的途径）或 蛋白酶体（VPU介导的途径）。艾滋病毒的努力水平可以说是无与伦比的 - 没有其他主机 包括众所周知的限制因素在内的因素以这种多方面的方式被拮抗。这暗示着 在感染细胞中恢复CD4水平可能会严重损害该病毒，并且显着有益 到主持人。但是，由于缺乏，设计或开发恢复CD4水平的疗法受到了极大的阻碍 关于相关分子组件的高分辨率结构信息，例如如何nef和vpu 将CD4招募到被劫持的主机贩运和退化机器中。在这个项目中，我们将解决如此高的 决议结构以获取这种药物发现方法所需的知识。我们的具体目的是： 1）阐明病毒NEF蛋白如何劫持网格蛋白衔接蛋白AP1以实现CD4的保留率 在内体中，支持CD4向溶酶体递送以降解。 2）揭示NEF如何劫持宿主运输蛋白ALIX将CD4引导到多细胞体和 溶酶体降解；调查以及如何，如果是这样，ALIX样蛋白PTPN23参与 在NEF介导的CD4和/或其他宿主因子的降解中。 3）阐明病毒VPU蛋白如何靶向ER中新合成的CD4以介导其多泛素化 通过β-TRCP/Cullin1复合物的国家，从而将CD4重定向到蛋白酶体降解。 这项工作的成功完成应揭示设计和/或开发新颖的疗法的机会 能够破坏HIV诱导的CD4降解的猿类，从而恢复受感染细胞的CD4以抑制HIV 复制甚至消除了感染。