A. Schematic diagram of putative phosphorylation cascades in EBNA1 a.a. 380-400. Consensus sites and comments for indicated kinase are as follows: ERK2 (PxS/TP or xxS/TP, CaMK II (RxxS/T), CDK1 (S/TPxR/K), CK1* (SxxS/T), GSK3b* (SxxxS), bold S/T (phosphorylation site), underlined S (prior phosphorylation site needed for subsequent phosphorylation at bold S), *cascade (prior phosphorylation)-dependent phosphorylation. B. Model of EBNA1-ERK2 interaction. A putative ERK docking motif (521DOCK528) on EBNA1 mediates a direct interaction with ERK2 and phosphorylation at S383 but is dispensable for in vivo interaction. An unknown protein linker (X) likely mediates ERK2 and EBNA1 interaction in vivo through an unknown site (BIND?-?) on EBNA1.