Fig. 4: Entry of SARS-CoV-2 into a Susceptible Host Cell by Envelope Fusion and by Endocytosis

1. Following adsorption of the SARS-CoV-2 S protein to an ACE-2 enzyme on a host cell, cleavage of the S protein by a surface host cell protease activates the S2 subunit of the S protein which enables the viral envelope to fuse with the plasma membrane of the host cell (1A) allowing the viral nucleocapsid to enter the host cell's cytoplasm (1B).

2. Following adsorption of the SARS-CoV-2 S protein to an ACE-2 enzyme on a host cell, the virus is taken in by endocytosis and is placed in an endosome (2A). Cleavage of the S protein by a host cell protease activates the S2 subunit of the S protein which enables the viral envelope to fuse with the membrane of the endosome (2B) allowing the viral nucleocapsid to enter the host cell's cytoplasm (2C).

Illustration of the entry of SARS-CoV-2 into a Susceptible Host Cell by Envelope Fusion and by Endocytosis .jpg by Gary E. Kaiser, Ph.D.
Professor of Microbiology, The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work at https://cwoer.ccbcmd.edu/science/microbiology/index_gos.html.

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Last updated: Feb., 2021
Please send comments and inquiries to Dr. Gary Kaiser