Enolase 1 suppresses influenza A virus replication by blocking the nuclear import of the viral ribonucleoprotein complex

Influenza A viruses (IAVs) pose a severe threat to humans and animals, and rely on numerous proviral host proteins to support their replication. Nevertheless, multiple host factors exert restrictive effects on the IAV life cycle through different mechanisms. Enolase 1 (ENO1), a glycolytic enzyme, has been identified to affect viral replication of limited viruses; and its role in the IAV life cycle remains poorly understood. In this study, we found that ENO1 is a negative regulator of IAV replication. Knockdown of ENO1 significantly enhanced IAV propagation, whereas its overexpression dramatically reduced viral growth. Further, ENO1 reduced IAV replication independent of the glycolysis pathway. ENO1 interacted with viral nucleoprotein (NP) and attenuated viral polymerase activity through blocking the nuclear import of the viral ribonucleoprotein (vRNP) complex. Mechanistically, ENO1 impaired the binding of NP to importin α3, but not to importin α1, α5, or α7, thereby preventing the nuclear import of the vRNP complex and suppressing IAV replication. Taken together, our study uncovered a novel function of ENO1 in IAV replication, and shed new light on understanding virus-host interactions. Our findings indicated that ENO1 may be a promising target for the development of antiviral drugs.