Fig. 3

A simplified scheme of the life cycle of SARS-CoV-2 inside the host cell (with organ injury in COVID-19). (1) SARS-CoV-2 requires activation by the serine protease TMPRSS2 for optimal cell entry and the viral Spike glycoprotein of the virion binds to the cellular receptor ACE2 and enters target cells through an endosomal pathway. (2) Following the entry of the virus into the host cell, the viral RNA is released into cytoplasm. (3) After release of the viral genome the viral polymerase protein is translated from the genomic RNA. (4) Replication occurs and new ssRNA(+) are synthesized. (5) In transcription, a nested set of sub-genomic RNAs (sgRNAs) is produced (6) Viral structural proteins (S, E, and M) are translated from the RNA inserted into the endoplasmic reticulum, N in citoplasm and move to the endoplasmic reticulum-Golgi intermediate compartment. (7) The viral proteins formed in ER migrate to the Golgi apparatus and are assembled with the nucleocapsid. (8) Formation of mature virion. Finally, (9) the virions are released via the constitutive exocytic pathway out of the cell. In the SARS-CoV-2 infection multi-organ are injured in COVID-19 patients. S, spike protein; E, envelope protein; M, membrane protein; N, nucleocapsid protein; ER, endoplasmic reticulum. This figure was created using Servier Medical Art templates, which are licensed under a Creative Commons Attribution 3.0 Unported License; https://smart.servier.com