The current outbreak of coronavirus disease 2019 (COVID-19) in Wuhan,China,has posed significant threats to international health.By Feb.20,2020,74 576 cases have been confirmed and over 2 118 deaths have reported in the Chinese mainland.Chinese administrations have carried out immediate and prompt measures to stop the spread of the virus.Wuhan city has been shut down since Jan.23,and more than 30 thousand medical workers have been recruited to Hubei province.Two temporary hospitals were constructed to treat severe pneumonia patients,and 15 mobile cabin hospitals were built to treat mild pneumonia cases.Significant improvement regarding the pathogenesis,epidemiology,and diagnosis and therapy for the COVID-19 has been achieved to stop the spread of the epidemics.

The emergence of novel coronavirus pneumonia which was named as coronavirus disease 2019 (COVID-19) by the World Health Organization, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has posed a serious threat to public health. Notably, COVID-19 has rapidly spread around the world and large amount of people have been infected. There is imminent need to investigate the pathogenesis of SARS-CoV-2 and develop effective therapeutic strategies to contain the epidemic. The spike (S) protein of SARS-CoV-2 mediates viral entry into target cells, with S1 subunit binding to a cellular receptor and S2 subunit fusing viral and host membranes. Angiotensin-converting enzyme 2 (ACE2), previously known as a cell receptor of severe acute respiratory syndrome coronavirus (SARS-CoV), is putatively responsible for mediating COVID-19. In this review, we detail our current understanding of the interaction between S protein and ACE2 in the process of virus infection and the potential pathogenesis of SARS-CoV-2, which has critical implications for exploring the potential therapeutic strategies for COVID-19.