Broad use of feline APN by alphacoronaviruses implicates cats in cross-species transmission

Coronaviruses continue to pose a global public health threat, and the increasing frequency of zoonotic spillover events highlights the crucial role of animal hosts in cross-species transmission. As companion animals, cats warrant attention for their potential involvement in coronavirus cross-species spread. Here, we show that feline aminopeptidase N (fAPN) functions as a shared receptor utilized by multiple alphacoronaviruses (α-CoVs), including human coronavirus 229E (HCoV-229E), transmissible gastroenteritis virus, and type-II feline infectious peritonitis virus, to mediate entry into feline cells. Structural and functional analyses reveal that distinct viruses engage fAPN through alternative binding sites, enabling multimodal receptor recognition, and demonstrating notable receptor compatibility. Animal challenge experiments further indicate that HCoV-229E showed detectable viral RNA and infectious virus in the feline respiratory tract, with no apparent clinical signs. Together, these findings establish fAPN as a shared receptor for diverse α-CoVs and reveal a molecular basis for receptor compatibility across viral lineages, providing insight into the determinants of coronavirus host range and cross-species transmission.IMPORTANCEZoonotic coronaviruses repeatedly threaten human health, yet the rules governing their ability to cross species remain incompletely understood. Cats live in close contact with humans and may act as hidden hosts for coronaviruses, but the molecular basis supporting cross-species infection in these animals is unclear. This study demonstrates that feline aminopeptidase N (fAPN) serves as a common receptor for several alphacoronaviruses (α-CoVs), including human coronavirus 229E (HCoV-229E), transmissible gastroenteritis virus, and type-II feline infectious peritonitis virus. These viruses recognize fAPN through distinct binding sites, highlighting the flexibility of receptor recognition. Additionally, HCoV-229E inoculation resulted in detectable viral RNA in the respiratory tract of cats, without apparent clinical signs. These results help explain why α-CoVs can move across host barriers and suggest that cats should be considered when assessing coronavirus spillover risks at the human-animal interface.