Role of Serine Proteases and Host Cell Receptors Involved in Proteolytic Activation, Entry of SARS-CoV-2 and Its Current Therapeutic Options

The current global pandemic of a novel severe acute respiratory syndrome coronavirus-2 continues with its public health disaster beginning from late December 2019 in Wuhan, Hubei province, China. The scientific community has tried to fight against this novel coronavirus through vaccine development and designing different candidate drugs. However, there is no well-defined therapy to prevent 2019-nCov infection, thus complete prevention of the virus remains difficult. Therefore, it is a critical factor for death of millions worldwide. Many clinical trials and insights are ongoing in the struggle with this pandemic of SARS-CoV-2. SARS-CoV-2 entry into the host cell requires host cell angiotensin-converting enzyme-2 (ACE2) and glucose regulated protein 78 (GRP78). On the other hand, proteolytic activation of the viral spike protein (S protein) needs the host cell serine proteases, including transmembrane serine protease 2 (TMPRSS2), cathepsins, trypsin and furin. This review focuses on the protein involved in the mechanism of entry, and proteolytic activation. In addition, it looks at current therapeutic options for SARS-CoV-2.