Kashuba О. The role of the interaction of cellular proteins with nuclear antigens encoded by Epstein-Barr virus, the transformation of B- lymphocytes

The present work is devoted to a study on the interaction between B cell and latent proteins encoded by Epstein-Barr virus (EBV) namely the search for cellular proteins that bind to the EBV-encoded nuclear antigens EBNA-3, -5 and -6, in order to identify the molecular mechanisms of malignant transformation of B cells upon EBV infection. Using the yeast two-hybrid system and mass-spectrometry we have identified 17 cellular proteins that interact with nuclear antigens EBNA-3, -5 and -6. The identified proteins are involved in cell metabolism (PHD1, PHD2, HIF1а, UCKL-1), the p53 (p14ARF, MDM2) and RB-E2F (MRPS18-2) pathways, the signaling pathway of nuclear receptors (XAP-2, AhR, VDR, HIF1а), and the control of apoptosis (MDM2, AhR, VDR). A Warburg effect, or aerobic glycolysis was observed in transformed B cells, caused by stabilization of HIF1а protein. This was due to inhibiting of its degradation as a consequence of a binding between prolylhydroxylases PHD1 and PHD2 with EBNA-5 and EBNA-3, respectively. The trasactivating ability of p53 protein was blocked in lymphoblastoid cells due to formation of tri-molecular complex that consisted of p53, MDM2, and EBNA-5. We have shown also that overexpression of MRPS18-2 protein, which can form tri-molecular complexes with EBNA-6 and RB in B cells, leads to transformation of primary rat fibroblasts. This data extend the understanding of the mechanism of malignant transformation of B cells upon infection with Epstein-Barr virus.