Characterizing the Role of EWI-2 Palmitoylation During HIV-1 Infection
Conference Year
January 2021
Abstract
Human Immunodeficiency Virus type 1 (HIV-1) encodes the accessory proteins Nef, Vif, Vpr, and Vpu which alter the host cellular environment to promote virus production and evade immune detection. Vpu downregulates host surface factors including tetraspanins and EWI-2, two known fusion inhibitors. Fusion inhibitory proteins prevent excessive HIV-1-induced cell-cell fusion through their localization at the virological synapse (VS); A cellular junction created when the viral protein Envelope (Env) on the surface of an infected producer cell binds to the CD4 receptor on the surface of an uninfected target cell, allowing for efficient cell-to-cell virus transmission. This reveals the dichotomy of EWI-2 and CD81 in promoting viral spread, as they are downregulated, yet recruited to the VS to prevent cell-cell fusion. Palmitoylation of the EWI-2 cytoplasmic tail is required for interactions with CD81 yet remains relatively unstudied in the context of HIV-1 infection. Given that the EWI-2-CD81 interaction is crucial for their regulatory functions, we hypothesize that palmitoylation is necessary for Vpu-mediated EWI-2 downregulation as well as accumulation at the VS. Flow cytometry and microscopy will be used on cells expressing palmitoylation deficient EWI-2 to analyze their effect on accumulation at the VS and downregulation by Vpu.
Primary Faculty Mentor Name
Markus Thali
Graduate Student Mentors
Emily Whitaker
Status
Graduate
Student College
College of Agriculture and Life Sciences
Program/Major
Microbiology and Molecular Genetics
Primary Research Category
Biological Sciences
Secondary Research Category
Health Sciences
Characterizing the Role of EWI-2 Palmitoylation During HIV-1 Infection
Human Immunodeficiency Virus type 1 (HIV-1) encodes the accessory proteins Nef, Vif, Vpr, and Vpu which alter the host cellular environment to promote virus production and evade immune detection. Vpu downregulates host surface factors including tetraspanins and EWI-2, two known fusion inhibitors. Fusion inhibitory proteins prevent excessive HIV-1-induced cell-cell fusion through their localization at the virological synapse (VS); A cellular junction created when the viral protein Envelope (Env) on the surface of an infected producer cell binds to the CD4 receptor on the surface of an uninfected target cell, allowing for efficient cell-to-cell virus transmission. This reveals the dichotomy of EWI-2 and CD81 in promoting viral spread, as they are downregulated, yet recruited to the VS to prevent cell-cell fusion. Palmitoylation of the EWI-2 cytoplasmic tail is required for interactions with CD81 yet remains relatively unstudied in the context of HIV-1 infection. Given that the EWI-2-CD81 interaction is crucial for their regulatory functions, we hypothesize that palmitoylation is necessary for Vpu-mediated EWI-2 downregulation as well as accumulation at the VS. Flow cytometry and microscopy will be used on cells expressing palmitoylation deficient EWI-2 to analyze their effect on accumulation at the VS and downregulation by Vpu.