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Identification of domains in the HIV Envelope glycoprotein cytoplasmic tail required for particle incorporation

Lerner, Grigoriy
http://orcid.org/0000-0003-4876-0597
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1703170158488023

Abstract Details

2023, PhD, University of Cincinnati, Medicine: Molecular Genetics, Biochemistry, & Microbiology.
The human immunodeficiency virus (HIV) is the viral pathogen underlying the ongoing AIDS pandemic. Current estimates place the number of infected individuals worldwide at nearly 40 million people, and the number of infected is still growing every year. Although modern antiretroviral therapy (ART) regimens are effective at halting the progression of disease, there is still no cure or vaccine available. The only viral antigen present on the surface of particles is the HIV Envelope glycoprotein (Env), and its expression on the surface is tightly regulated. Surprisingly, Env is endocytosed rapidly upon reaching the plasma membrane (PM), requiring recycling pathways in order to return to the PM site of particle assembly. Understanding how Env navigates the endosomal recycling compartment (ERC) could lead to development of novel therapeutics and improved vaccine design. The mechanisms underlying Env trafficking to the site of assembly following endocytosis are poorly defined. The cytoplasmic tail (CT) of Env contains structural determinants required for incorporation in physiologically relevant cells. The CT contains a long unstructured region followed by three amphipathic helices, and mediates interactions with cellular trafficking machinery including clathrin, clathrin adaptor protein, retromer, and Rab11 family interacting protein-1C (FIP1C). We created a series of truncation and point mutants in the CT in order to assess their ability to direct Env trafficking and particle incorporation. We initially utilized a truncated form of FIP1C that collapses the ERC as a marker of Env trafficking to this compartment. Trafficking to the ERC required specific tryptophan-based motifs in the LLP3 region of the CT. Disruption of these motifs eliminated ERC trafficking and rendered Env defective for incorporation into particles. This work was then extended to examine the trafficking of Env to the tubular recycling endosome (TRE). This work identified for the first time a prominent association of endocytosed Env with the TRE, as marked by its defined constituents MICAL-L1, EHD1 and Rab10. Env association with the TRE required an intact CT, while the tryptophan mutants in LLP3 failed to associate with the TRE. Remarkably, knockdown of critical TRE components greatly reduced Env incorporation in relevant cell types such as T cell lines and macrophages. These findings are the strongest to date indicating that cellular recycling pathways are essential for Env incorporation and HIV replication.
Paul Spearman, M.D. (Committee Chair)
Jason Blackard, Ph.D. (Committee Member)
Richard Thompson, Ph.D. (Committee Member)
Thomas Thompson, Ph.D. (Committee Member)
William Miller, Ph.D. (Committee Member)
115 p.
Virology
HIV; gp160; Env; cytoplasmic tail; FIP1C; tubular recycling endosome

Recommended Citations

Citations

  • Lerner, G. (2023). Identification of domains in the HIV Envelope glycoprotein cytoplasmic tail required for particle incorporation [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1703170158488023

    APA Style (7th edition)

  • Lerner, Grigoriy. Identification of domains in the HIV Envelope glycoprotein cytoplasmic tail required for particle incorporation. 2023. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1703170158488023.

    MLA Style (8th edition)

  • Lerner, Grigoriy. "Identification of domains in the HIV Envelope glycoprotein cytoplasmic tail required for particle incorporation." Doctoral dissertation, University of Cincinnati, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1703170158488023

    Chicago Manual of Style (17th edition)

ucin1703170158488023
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This open access ETD is published by University of Cincinnati and OhioLINK.