Table 1.

Functions of SARS-CoV-2 proteins.

Name of Protein	Function	Reference
S	The spike S-protein binds to its receptor (ACE2) and perforates (after its cleavage) the double membrane composed of the PM and endosomal membrane.	[31,33,38]
E	The envelope (E) protein is crucial for budding and replication	[52,58,59,63,64,65,66]
M	The triple-spanning membrane M protein binds to the nucleocapsid and generates the curvature of the host cell membrane. The cytoplasmic domains of M proteins homo-oligomerize. The M–E complex ensures the uniform size of viral particles for viral maturation and mediates virion release.	[62]
N	The N protein forms biomolecular condensates with RNA.	[61,63]
NSP1	NSP1 binds to 18S ribosomal RNA in the mRNA entry channel of the ribosome and leads to global inhibition of mRNA translation upon infection. It degrades host mRNA and inhibits IFN signaling. NSP1 suppress IFN-I signaling.	[67,68]
NSP2	NSP2 induces repression of mRNA translation, impairing interferon production.	[69]
NSP3	NSP3/papain-like protease is responsible for cleaving viral polyproteins during replication. NSP3 is the largest protein encoded by the coronavirus. It cleaves viral proteins. NSP3 reverses PARP9/DTX3L-dependent ADP-ribosylation induced by interferon signaling.	[70,71]
NSP4	NSP4 induces pro-inflammatory mitochondrial DNA release in inner membrane-derived vesicles.	[72]
NSP5	NSP5/3C-like protease is responsible for cleaving viral polyproteins during replication. NSP5 exhibits catalytic activity and interferon antagonism. NSP5 activates the NF-κB pathway.	[73,74,75,76]
NSP6	NSP6 participates in the biogenesis of the SARS-CoV-2 replication organelle. It forms double membrane vacuoles (DMVs). NSP6 impairs lysosome acidification to inhibit autophagic flux. NSP6 suppress IFN-I signaling. It triggers NLRP3-dependent pyroptosis.	[14,76,77]
NSP7	They form a dexadecameric complex. They form polymerase complex consisting of the NSP12 catalytic subunit and NSP7–NSP8 cofactors. Processing clamp for RdRp. NSP8 and NSP9 bind to the 7SL RNA in the signal recognition particle and interfere with protein trafficking to the cell membrane upon infection.	[67,78]
NSP8
NSP9	RNA binding. NSP8 and NSP9 bind to the 7SL RNA in the signal recognition particle and interfere with protein trafficking to the cell membrane upon infection.	[67]
NSP10	SARS-CoV-2 NSP10/NSP14-ExoN and NSP16 functions as an exoribonuclease with NSP14.	[79]
NSP11	Real function is unclear. NSP11 has a helical propensity.	[80]
NSP12	RNA-dependent RNA-cap2′-O-methyltransfeaze. Viral mRNA capping protecting it from RNases and RNA polymerase. Viral replication and transcription. Forms polymerase complex consisting of the NSP12 catalytic subunit and NSP7-NSP8 cofactors. NSP12 is the viral RNA-dependent RNA polymerase (RdRp) and suppresses host antiviral responses.	[78,81]
NSP13	RNA helicase, 5′-triphosphatase. 2 NSP13, NSP14, and NSP15 function as potent interferon antagonists.	[82,83,84,85,86]
NSP14	NSP13, NSP14, and NSP15 function as potent interferon antagonists.	[86,87,88,89]
NSP15	Endoribonuclease NSP13, NSP14, and NSP15 function as potent interferon antagonists.	[86]
NSP16	2′-O-methyltransferase NSP16,	[14,90]