Date of Award
Anne M. Pumfery
Kaposi's sarcoma, Herpesvirus, Bcl-2 protein, Apoptosis
Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of various diseases, and it encodes a Bcl-2 homolog, KS-Bcl-2. The Bcl-2 family is important in regulating cellular apoptosis. Pro-apoptotic Bcl-2 family members promote apoptosis through mitochondrial pore formation by Bak and Bax, or through BH3 only domain activators and sensitizers. Anti-apoptotic members, such as cellular Bcl-2 prevent apoptosis through interactions with pro-apoptotic proteins, for instance inhibiting pore formation by binding to Bak and/or Bax. Even though, KS-Bcl-2 has been shown to have an anti-apoptotic function like its homolog, it does not bind to either Bak or Bax, and little is known about the mechanism behind KS-Bcl-2's function. A second mitochondrial apoptotic pore is the mPTP, which is made up of ANT and VDAC. Bcl-2 and Bcl-xL have been shown to prevent apoptosis through interactions with these proteins. In order to further investigate the mechanism behind KS-Bcl-2's anti-apoptotic function the localization and binding to the mPTP needed to be determined. KS-Bcl-2 was transfected into Vero cells and then localization was observed under normal and apoptotic conditions. Under normal conditions KS-Bcl-2 localized to the mitochondria, cytoplasm, and nucleus and during apoptosis primarily the mitochondria. Furthermore, to evaluate KS-Bcl-2's interaction with mPTP proteins a OST-pull down assay was performed using isolated GST-KS-Bcl-2 and mitochondrial proteins, and then evaluated for VDAC. It was observed that VDAC and KS-Bcl-2 do interact, and that this interaction could potentially be the mechanism behind KS-Bcl-2's anti-apoptotic function. Further studies are needed to determine the functionality of this interaction.
St.Angelo, Erin T., "Localization and Binding Characteristics of Kaposi's Sarcoma-Associated Herpesvirus Bcl-2 Protein in the Prevention of Apoptosis" (2010). Seton Hall University Dissertations and Theses (ETDs). 2456.