Purdue University Graduate School
Balindile Bhekiwe Motsa thesis (FINAL).pdf (5.46 MB)

Evaluating the role of the Ebola virus (EBOV) matrix protein (VP40) surface charge and host cell calcium levels on EBOV plasma membrane assembly and budding.

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posted on 2024-04-24, 02:48 authored by Balindile Bhekiwe MotsaBalindile Bhekiwe Motsa

The Ebola virus (EBOV) is a filamentous RNA virus which causes severe hemorrhagic fever. It is one of the most dangerous known pathogens with a high fatality rate. Multiple outbreaks of EBOV have occurred since the 1970s with the most widespread outbreak starting in December 2013. This outbreak continued through May of 2016 and had a fatality rate of approximately 50%. EBOV outbreaks are recurrent because the virus is still present in animal reservoirs. Despite multiple EBOV outbreaks we still lack a clear understanding of how new viral particles are formed and spread through virus assembly and release. Given the widespread global travel, EBOV now poses a threat to the entire world. EBOV encodes for the matrix protein, VP40, which is one of the most conserved viral proteins. VP40 can form different structures leading to different functions of the protein in different stages of the EBOV life cycle. The VP40 dimer traffics to the inner leaflet of the plasma membrane to facilitate assembly and budding. The VP40 octameric ring has been implicated in transcriptional regulation. This thesis focuses on understanding in further detail the determinates of VP40 plasma membrane assembly and exit from an infected cell.

The assembly and trafficking of VP40 to the plasma membrane requires a network of protein-protein and lipid-protein interactions (PPIs and LPIs). Studying these interfaces is important for understanding how VP40 structure and function regulates trafficking and assembly and can shed light on therapeutic strategies to target EBOV. The alteration of host cell Ca2+ levels is one of the strategies that viruses use to perturb the host cell signaling transduction mechanism in their favor. Evidence has emerged demonstrating that Ca2+ is important for the assembly and budding of EBOV in a VP40-dependent manner. The relationship between intracellular Ca2+ levels and EBOV matrix protein VP40 function is still unknown. In this work we utilize biophysical techniques to study the role of LPIs and intracellular Ca2+ on VP40 dynamics at the plasma membrane and key residues for assembly and budding. This work highlights the sensitivity of slight electrostatic changes on the VP40 surface for assembly and budding and a critical interaction between Ca2+ and the VP40 dimer that are important for lipid binding at the plasma membrane.


Degree Type

  • Doctor of Philosophy


  • Medicinal Chemistry and Molecular Pharmacology

Campus location

  • West Lafayette

Advisor/Supervisor/Committee Chair

Dr. Robert Stahelin

Additional Committee Member 2

Dr. Douglas LaCount

Additional Committee Member 3

Dr. Richard Kuhn

Additional Committee Member 4

Dr. Seung-Oe Lim