Structural and functional analyses reveal promiscuous and species specific use of ephrin receptors by Cedar virus

Significance Nipah and Hendra viruses are pathogenic zoonotic henipaviruses, transmitted from wildlife to humans, and potential epidemic threats. Zoonoses from wildlife hosts to humans require overcoming barriers that limit cross-species transmission. Successful usage of virus entry receptors represents a bottleneck to zoonosis. Conserved ephrins are recognized entry receptors for henipaviruses like Nipah virus. Here, we characterize the ephrin entry receptor usage of Cedar virus (CedV), a related henipavirus with unknown zoonotic potential that is nonpathogenic in animals known to be susceptible to Nipah and Hendra disease. We discovered that CedV utilizes 4 different ephrins, 3 of which are unique receptors for CedV, and determined that a single natural amino acid difference between human and mouse ephrin-A1 can dictate functional receptor usage.
Cedar virus (CedV) is a bat-borne henipavirus related to Nipah virus (NiV) and Hendra virus (HeV), zoonotic agents of fatal human disease. CedV receptor-binding protein (G) shares only ∼30% sequence identity with those of NiV and HeV, although they can all use ephrin-B2 as an entry receptor. We demonstrate that CedV also enters cells through additional B- and A-class ephrins (ephrin-B1, ephrin-A2, and ephrin-A5) and report the crystal structure of the CedV G ectodomain alone and in complex with ephrin-B1 or ephrin-B2. The CedV G receptor-binding site is structurally distinct from other henipaviruses, underlying its capability to accommodate additional ephrin receptors. We also show that CedV can enter cells through mouse ephrin-A1 but not human ephrin-A1, which differ by 1 residue in the key contact region. This is evidence of species specific ephrin receptor usage by a henipavirus, and implicates additional ephrin receptors in potential zoonotic transmission.