Two amino acids of a conserved E-L-E-F-N motif in the N-terminal region of KSHV and RRV gH are essential for Eph interaction.

<p><b>A</b> Domain structure of KSHV and RRV gH. Multiple sequence alignment of domain I of gH of KSHV and the two RRV isolates 26–95 and 17577 (enlarged inset, numbers corresponding to KSHV gH). The EBV gH sequence is included as a reference. <b>B</b> Mutational scan of the N-terminal region of KSHV gH identifies EphA2-interacting residues. V5-tagged KSHV gH mutants were co-expressed with Flag-tagged KSHV gL. gH-V5/gL-Flag complexes were immunoprecipitated in the presence of full-length EphA2-myc using monoclonal antibody to the V5-tag and precipitates were analyzed by Western blot. KSHV gH alone serves as negative control. <b>C</b> Mutational scan of the N-terminal region of RRV gH identifies EphB3-interacting residues. V5-tagged gH mutants were co-expressed with Flag-tagged RRV gL. gH-V5/gL-Flag complexes were immunoprecipitated in the presence of full-length EphB3-myc using monoclonal antibody to the V5-tag and precipitates were analyzed by Western blot. RRV gH alone serves as negative control. Residues in the conserved E-L-E-F-N motif that are critical for Eph interaction are indicated by black lines. Asterisks indicate non-specific bands. Abbreviations: D: domain, TM: transmembrane domain, SP: signal peptide, IVD: intravirion domain, IP: immunoprecipitation, IB: immunoblotting.</p>