3篇Nature同时发布介绍HIV-1与人类蛋白新作用

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Three papers published simultaneously in Nature have provided new insights into the network of interactions between HIV-1 and human proteins, and identified potential new targets for therapeutic intervention.

第一篇  Global landscape of HIV–human protein complexes
格莱斯顿研究院（Gladstone Institutes）科学家Nevan Krogan博士在旧金山加利福尼亚大学(UCSF)他的实验室进行了这项研究，利用AP-MS技术在HEK293、Jurkat细胞中筛选出与全部18种HIV-1蛋白相互作用的宿主蛋白。确定了497种人类艾滋病毒蛋白质生化反应，包括435种人类独有的蛋白质。 40％的这些相互作用被确定了在HEK293细胞和Jurkat细胞株；在灵长类动物中，许多受艾滋病毒劫持的宿主蛋白具有高度保守。
当研究团队分析了与每个艾滋病毒蛋白相关的宿主蛋白的功能类别后，发现宿主大部分分子都通过与HIV转录因子Tat作用参与转录过程。也有大部分宿主蛋白被认为参与了Vpu, Vpr, Vif（这3种蛋白被认为是HIV劫持泛素连接酶的辅助因子）相关的泛素化调节过程。同时还有一个值得注意的发现，HIV蛋白酶能切割降解eIF3d，而这个分子是真核转录起始因子3的一个亚基，同时也是目前已知具有抑制HIV复制的11种宿主蛋白之一。

Global landscape of HIV-human protein complexes

Stefanie J?ger, Peter Cimermancic, Natali Gulbahce, Jeffrey R. Johnson, Kathryn E. McGovern, Starlynn C. Clarke, Michael Shales, Gaelle Mercenne, Lars Pache, Kathy Li, Hilda Hernandez, Gwendolyn M. Jang, Shoshannah L. Roth, Eyal Akiva, John Marlett, Melanie Stephens, Ivan D'Orso, Jason Fernandes, Marie Fahey, Cathal Mahon, Anthony J. O'Donoghue, Aleksandar Todorovic, John H. Morris, David A. Maltby, Tom Alber, Gerard Cagney, Frederic D. Bushman, John A. Young, Sumit K. Chanda, Wesley I. Sundquist, Tanja Kortemme, Ryan D. Hernandez, Charles S. Craik, Alma Burlingame, Andrej Sali, Alan D. Frankel, Nevan J. Krogan.

Abstract： Human immunodeficiency virus (HIV) has a small genome and therefore relies heavily on the host cellular machinery to replicate. Identifying which host proteins and complexes come into physical contact with the viral proteins is crucial for a comprehensive understanding of how HIV rewires the host's cellular machinery during the course of infection. Here we report the use of affinity tagging and purification mass spectrometry to determine systematically the physical interactions of all 18 HIV-1 proteins and polyproteins with host proteins in two different human cell lines (HEK293 and Jurkat). Using a quantitative scoring system that we call MiST, we identified with high confidence 497 HIV-human protein-protein interactions involving 435 individual human proteins, with ~40% of the interactions being identified in both cell types. We found that the host proteins hijacked by HIV, especially those found interacting in both cell types, are highly conserved across primates. We uncovered a number of host complexes targeted by viral proteins, including the finding that HIV protease cleaves eIF3d, a subunit of eukaryotic translation initiation factor 3. This host protein is one of eleven identified in this analysis that act to inhibit HIV replication. This data set facilitates a more comprehensive and detailed understanding of how the host machinery is manipulated during the course of HIV infection.


楼主：ipsvirus

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第二篇  Vif hijacks CBF-β to degrade APOBEC3G and promote HIV-1 infection

在第一篇文章的实验中，Krogan博士首先对所有潜在相互作用进行了系统、全面分析，此相互作用出现在机体产生的蛋白质（人体蛋白质）与病毒产生的蛋白质（HIV蛋白质）之间。其次，他将近500个这样的相互作用逐渐削整成一个，这一个似乎最有可能助长HIV感染：即人类蛋白质CBFβ与HIV蛋白Vif之间的相互作用。这就是他的第二篇文章。

通常在HIV感染期间，限制因子APOBEC3G发挥分子路障的作用，防止病毒到达其目标--CD4T白细胞，免疫系统的一个主要组成部分。但是，Krogan博士发现，当HIV蛋白Vif结合到人类蛋白质CBFβ时，Vif被强化，APOBE C3G降解。这种降解削弱了ABOBEC3G阻止HIV的能力，病毒自由地感染CD4 T细胞。加州大学旧金山分校的研究团队的结论是：“扰乱CBF -β- Vif的互动的方法可能使HIV-1受限制，为目前主要针对病毒蛋白的抗病毒治疗提供了一个补充”

Vif hijacks CBF-β to degrade APOBEC3G and promote HIV-1 infection

Stefanie J?ger, Dong Young Kim, Judd F. Hultquist, Keisuke Shindo, Rebecca S. LaRue, Eunju Kwon, Ming Li, Brett D. Anderson, Linda Yen, David Stanley, Cathal Mahon, Joshua Kane, Kathy Franks-Skiba, Peter Cimermancic, Alma Burlingame, Andrej Sali, Charles S. Craik, Reuben S. Harris, John D. Gross, Nevan J. Krogan.

Abstract： Restriction factors, such as the retroviral complementary DNA deaminase APOBEC3G, are cellular proteins that dominantly block virus replication. The AIDS virus, human immunodeficiency virus type 1 (HIV-1), produces the accessory factor Vif, which counteracts the host's antiviral defence by hijacking a ubiquitin ligase complex, containing CUL5, ELOC, ELOB and a RING-box protein, and targeting APOBEC3G for degradation. Here we reveal, using an affinity tag/purification mass spectrometry approach, that Vif additionally recruits the transcription cofactor CBF-β to this ubiquitin ligase complex. CBF-β, which normally functions in concert with RUNX DNA binding proteins, allows the reconstitution of a recombinant six-protein assembly that elicits specific polyubiquitination activity with APOBEC3G, but not the related deaminase APOBEC3A. Using RNA knockdown and genetic complementation studies, we also demonstrate that CBF-β is required for Vif-mediated degradation of APOBEC3G and therefore for preserving HIV-1 infectivity. Finally, simian immunodeficiency virus (SIV) Vif also binds to and requires CBF-β to degrade rhesus macaque APOBEC3G, indicating functional conservation. Methods of disrupting the CBF-β-Vif interaction might enable HIV-1 restriction and provide a supplement to current antiviral therapies that primarily target viral proteins.

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第三篇 T-cell differentiation factor CBF-β regulates HIV-1 Vif-mediated evasion of host restriction
这篇文章也是报道发现与HIV-1 Vif蛋白相互作用的宿主细胞因子—CBFβ，与第二篇文章一起是不同实验室同时发现Vif蛋白作用机理。

该文章第一作者为吉林大学白求恩第一医院张文艳副教授，通讯作者为吉林大学白求恩第一医院千人计划特聘教授于晓方教授，文章第一完成单位为吉林大学白求恩第一医院。

T-cell differentiation factor CBF-β regulates HIV-1 Vif-mediated evasion of host restriction

Wenyan Zhang, Juan Du,         Sean L. Evans, Yunkai Yu & Xiao-Fang Yu

The human APOBEC3 cytidine deaminases are potent inhibitors of diverse retroviruses, including human immunodeficiency virus-1 (HIV-1). HIV-1 Vif forms an E3 ubiquitin ligase complex with cullin 5 (CUL5), elongin B and elongin C , which promotes the polyubiquitination and degradation of APOBEC3 substrates. Here we demonstrate in human T cells that core binding factor β (CBF-β) is a key regulator of the evasion of HIV-1 from the host defence mediated by APOBEC3. CBF-β, the non-DNA-binding subunit of a heterodimeric transcription factor, regulates the folding and DNA-binding activity of partner RUNX family proteins, which have important roles in the development and differentiation of diverse cell types, including T lymphocytes. In our study, knockdown of endogenous CBF-β blocked Vif-induced APOBEC3G polyubiquitination and degradation. CBF-β was not required for the interaction between Vif and APOBEC3G, yet was essential for the assembly of the Vif–CUL5 E3-ubiquitin-ligase complex. CBF-β proved to be a unique regulator of primate lentiviral Vif and not a general component of the CUL5 E3 ubiquitin ligase. We show that Vif and CBF-β physically interact, and that the amino-terminal region of Vif is required for this interaction. Furthermore, interactions with Vif required regions in CBF-β that are not involved in RUNX protein binding. Considering the importance of the interaction between Vif and CBF-β, disrupting this interaction represents an attractive pharmacological intervention against HIV-1.