Assaying the Activity of Kinases Regulated by LMP1

Latent infection of B lymphocytes by Epstein-Barr virus (EBV) results in the immortalization of the infected cells (1 ,2 ). In vitro, expression of latent membrane protein 1 (LMP1) is essential for the proliferation of EBV-immortalized B cells in that LMP1 simulates an activated CD40 receptor (3 ). LMP1 exerts its effects by initiating both anti-apoptotic and proliferative, growth factor-like signals in the cell (4 ). Special interest has focused on the molecular basis of LMP1 function because LMP1 is the only EBV protein that also has an oncogenic potential in non-B cells. LMP1 transforms rodent fibroblasts in vitro, proving it to be a true viral oncogene (5 ,6 ). As such the signaling pathways impacted by LMP1 are likely to play important roles in the regulation of proliferation and transformation of the target cell.