Date of Award
1-2026
Document Type
Thesis
Degree Name
Master of Science (MS)
College/School
College of Science and Mathematics
Department/Program
Biology
Thesis Sponsor/Dissertation Chair/Project Chair
Eli Il-Hyung Lee
Committee Member
Quinn Vega
Committee Member
Christos Suriano
Abstract
HIV entry is initiated by a high-affinity interaction between the viral envelope glycoprotein gp120 and CD4 receptors, which triggers conformational changes in gp120 that expose the third variable (V3) loop and enable subsequent engagement with the co-receptor CCR5 or CXCR4 to facilitate membrane fusion. Although HIV-1 and HIV-2 broadly share this envelope mediated entry cascade, differences in virulence remain unresolved at a molecular level. Upon viral entry, the Endosomal Sorting Complex Required for Transport (ESCRT) machinery is co-opted to enable membrane budding through recognition of polymeric ubiquitin (UB) cargos. However, how such ubiquitin-dependent organization could contribute to the efficiency of cargo sorting mechanisms through biomolecular condensates and membrane phase separation remain poorly understood. Here, synthetic lipid membrane systems were used to reconstitute gp120–CCR5 interactions and polyubiquitin cargo clustering in vitro. Representative peptides from the CCR5 N-terminus were tethered to supported lipid bilayers (SLB) and giant unilamellar vesicles (GUV) to quantify binding dynamics of HIV-1 and HIV-2 based on V3 residue disparities. In parallel, modular synthetic UBD constructs and purified polyubiquitin proteins of varying length were applied to ternary GUV mixtures with raft-like compositions to evaluate if multivalent UB interactions serve as a mechanism for organizing and sorting ubiquitinated cargos. The results identify specific residues within the HIV-2 V3 loop that may contribute to reduced CCR5 engagement and reveal that ubiquitin cargos undergo valency-dependent phase separation on membranes. Thus, this work provides a plausible rationale for attenuated HIV-2 entry and insight into ubiquitin-driven cargo sorting in ESCRT-associated systems in disease contexts.
File Format
Recommended Citation
Okafor, Kamsy K., "Synthetic Lipid Membrane Systems Elucidate Protein Interactions in HIV Envelope-Mediated Coreceptor Fusion, and Polyubiquitin Cargo Clustering Relevant to Disease Patholoty" (2026). Theses, Dissertations and Culminating Projects. 1626.
https://digitalcommons.montclair.edu/etd/1626