The ectodomain of EphA2 and EphA4 are interchangeable for KSHV fusion activity, and the kinase activity of EphA4 is not needed for KSHV fusion activity. (A) Schematic drawing of the EphA2, EphA4, and, EphA2-EphA4 chimeras, including the ligand binding domain (LBD). (B) KSHV fusion with HEK293T cells transfected with control plasmid pcDNA3.1, EphA2, EphA4, or EphA2 and EphA4 chimeras, as indicated. (C) KSHV fusion with HEK293T cells transfected with control plasmid pcDNA3.1, EphA4, or EphA4 kinase-dead mutants as indicated. (B and C) Fusion activity of HEK293T cells transfected with pcDNA 3.1 was set to 100%.