The article discusses the identification of angiotensin-converting enzyme 2 (ACE2) as a functional receptor for the SARS coronavirus (SARS-CoV). The study demonstrates that ACE2 can be immunoprecipitated from Vero E6 cells by the S1 domain of the SARS-CoV spike protein, mediates fusion with S-protein-expressing cells, and promotes viral replication in a cell line otherwise inefficient for SARS-CoV infection. The presence of ACE2 is crucial for efficient viral replication, as anti-ACE2 antibodies specifically inhibited viral replication and syncytia formation. The tissue distribution of ACE2, particularly in the lungs and kidneys, aligns with the pathology of SARS, suggesting its role in viral replication in these organs. The identification of ACE2 as a SARS-CoV receptor will facilitate the development of targeted treatments, vaccines, and animal models for SARS.The article discusses the identification of angiotensin-converting enzyme 2 (ACE2) as a functional receptor for the SARS coronavirus (SARS-CoV). The study demonstrates that ACE2 can be immunoprecipitated from Vero E6 cells by the S1 domain of the SARS-CoV spike protein, mediates fusion with S-protein-expressing cells, and promotes viral replication in a cell line otherwise inefficient for SARS-CoV infection. The presence of ACE2 is crucial for efficient viral replication, as anti-ACE2 antibodies specifically inhibited viral replication and syncytia formation. The tissue distribution of ACE2, particularly in the lungs and kidneys, aligns with the pathology of SARS, suggesting its role in viral replication in these organs. The identification of ACE2 as a SARS-CoV receptor will facilitate the development of targeted treatments, vaccines, and animal models for SARS.