A broadly applicable cure for HIV-1 infection has remained elusive, in part, because the virus is able to circumvent host adaptive and innate immune responses. HIV-1 commandeers cellular pathways for its replication and antagonizes host proteins that inhibit viral replication. The HIV-1 accessory proteins, Vif, Vpr, Vpu and Nef, direct the degradation or mislocalization of cellular proteins that interfere with viral replicatio and persistence. Vif, Vpr and Vpu all usurp cellular ubiquitin ligases to degrade specific cellular proteins and facilitate replication. Some targets of these accessory proteins are known, but others are as yet undefined. Elucidating these viral-host cell interactions may reveal new viral dependencies on cellular proteins as well as new host antiviral proteins and viral countermeasures, revealing potential targets for antiretroviral therapy. The proposed project specifically examines the interaction between Vpu and the cellular ubiquitin pathway, determining the extent to which Vpu acts as a suicide inhibitor when targeting cellular proteins such as CD4 for degradation, the consequences these effects have for HIV-1 replication including viral cell-to-cell transmission. In addition, this study develops a novel experimental system to investigate the effects of HIV-1 gene expression and Vpu specifically on the modulation of cellular membrane proteins and global ubiquitination and degradation of cellular proteins, with the goal of attributing particular effects to the accessory gene vpu in the context f the complete repertoire of viral gene expression. In determining the host cell proteins modulated by HIV-1, this study will provide a better understanding of how HIV-1 manipulates the cellular environment to facilitate its replication and evade the immune response, which in turn will inform the development of new antiretroviral therapies. This proposal is intended to support the career development and further training of the candidate, who aims to extend her expertise in the molecular biology of HIV infection to include proficiency in the acquisition and analysis of proteomics and ubiquitinomics data sets. This project is expected to identify new cellular targets of HIV that will facilitate the development of independent lines of research, providing the foundation for the candidate to pursue additional sources of funding and foster a career as an independent physician- scientist.

Public Health Relevance

To counter cellular restriction factors and evade the antiviral immune response, HIV encodes four accessory proteins,Vif, Vpr, Vpu and Nef, which enhance virus replication by misdirecting host proteins within the cell and/or targeting them for degradation, often by hijacking the cellular ubiquitin-proteasome system. This proposal has two major goals: first, to define the interactions between the HIV-1 accessory protein Vpu and the host cell ubiquitin-proteasome pathway, investigating a possible role for Vpu in the cell-to-cell spread of HIV and its implications for antiretroviral sensitivity. The second aim is to develop a robust system to assess global changes in the host cell proteome and ubiquitinome induced by HIV-1 Vpu in order to identify novel viral-host interactions that could be exploited in the development of new HIV therapies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Clinical Investigator Award (CIA) (K08)
Project #
5K08AI112394-05
Application #
9614874
Study Section
Acquired Immunodeficiency Syndrome Research Review Committee (AIDS)
Program Officer
Kuo, Lillian S
Project Start
2015-01-01
Project End
2019-12-31
Budget Start
2019-01-01
Budget End
2019-12-31
Support Year
5
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of California, San Diego
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
804355790
City
La Jolla
State
CA
Country
United States
Zip Code
92093
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Ball, K Aurelia; Johnson, Jeffrey R; Lewinski, Mary K et al. (2016) Non-degradative Ubiquitination of Protein Kinases. PLoS Comput Biol 12:e1004898
Tokarev, Andrey; Stoneham, Charlotte; Lewinski, Mary K et al. (2015) Pharmacologic Inhibition of Nedd8 Activation Enzyme Exposes CD4-Induced Epitopes within Env on Cells Expressing HIV-1. J Virol 90:2486-502