Epstein-Barr Virus Latent Membrane Protein-1 Induces the Expression of SUMO-1 and SUMO-2/3 in LMP1-positive Lymphomas and Cells

Sadia Salahuddin,Emma K Fath,Tabithia Ross,Joseph S Pagano,Leslie Hilding,Ashley Ray,Gretchen L Bentz,Julia Shackelford,Natalie Biel,C Randall Moss,Matthew Varn,Wyatt T Cramblet,Akash Patel,Sheetal Patel,Angela Lowrey

doi:10.1038/s41598-018-36312-4

Abstract

Epstein-Barr Virus latent membrane protein-1 (LMP1) interacts with the SUMO-conjugating enzyme Ubc9, which induces protein sumoylation and may contribute to LMP1-mediated oncogenesis. After analyzing human lymphoma tissues and EBV-positive cell lines, we now document a strong correlation between LMP1 and sumo-1/2/3 or SUMO-1/2/3 levels, and show that LMP1-induced sumo expression requires the activation of NF-κB signaling through CTAR1 and CTAR2. Together, these results point to a second mechanism by which LMP1 dysregulates sumoylation processes and adds EBV-associated lymphomas to the list of malignancies associated with increased SUMO expression.

Highlights

Sumoylation is involved in central cellular processes, and multiple oncogene and tumor suppressor proteins undergo sumoylation, altering their function[14,15,16,17,18,19]
These findings confirm that latent membrane protein-1 (LMP1) expression increased total cellular SUMO levels, and while most SUMO localized to the nucleus, we show that LMP1 expression increases the levels of cytoplasmic SUMO
These results demonstrate that sumo, and SUMO, levels are increased in EBV-associated malignancies, and suggest that this induction occurs in an LMP1-dependent manner due to the activation of NF-κB by CTAR1 and CTAR2

Summary

Materials and Methods

Immunofluorescence microscopy was performed on LMP1-negative and LMP1-positive lymphomas in order to determine if increased sumo RNA levels correlated with increased SUMO protein levels in the tissue samples (Fig. 5a). The corrected total cell SUMO1 fluorescence was determined for LMP1-positive and LMP1-negative cells in the tissue samples and following transfections[64,65,66,67], and results showed that LMP1-positive cells had significantly (P < 0.05) higher SUMO1 levels than their LMP1-negative counterparts (Fig. 5c) These findings confirm that LMP1 expression increased total cellular SUMO levels, and while most SUMO localized to the nucleus, we show that LMP1 expression increases the levels of cytoplasmic SUMO. Because we previously documented that LMP1 induces the sumoylation of cellular proteins by interacting with Ubc[9] via CTAR38, these findings document a second mechanism by which LMP1 dysregulates cellular sumoylation processes and suggest that LMP1 regulates sumoylation processes by a multi-pronged approach

Discussion

Author Contributions

Findings

Additional Information