Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has posed substantial health threats and triggered widespread global economic disruption. The nucleocapsid (N) protein of SARS-CoV-2 is not only a key structural protein but also instrumental in mediating the host immune response, contributing significantly to inflammation and viral pathogenesis. Due to its immunogenic properties, SARS-CoV-2 N protein also interacts with host factors associated with various pre-existing inflammatory conditions and may possibly contribute to the long-term symptoms suffered by some COVID-19 patients after recovery-known as long COVID. This review provides a comprehensive overview of recent advances in elucidating the biological functions of the N protein. In particular, it highlights the mechanisms by which the N protein contributes to host inflammatory responses and elaborates on its association with long COVID and pre-existing inflammatory disorders.