Table 1. Roles of Nonstructural Proteins (nsps) of SARS-CoV-2.
| nsp | functionsa | refs |
|---|---|---|
| nsp1 | disrupting the mRNA export machinery to inhibit host gene expression; inhibiting host protein translation; inhibiting IFN pathway | (633−636) |
| nsp2 | linking viral transcription within the viral replication–transcription complex (RTC) to the initiation of translation | (637) |
| nsp3 | essential component of the replication/transcription complex; also responsible for inhibiting host innate immune response, promoting cytokine expression, and cleaving viral polypeptides | (638−640) |
| nsp4 | critical role in the organization and stability of DMVs | (641−643) |
| nsp5 | 3CLpro and Mpro protease activity; blocking the IFN pathway | (644−646) |
| nsp6 | organizing DMVs; restoring autophagosome expansion; involved in autophagy | (643), (647), (648) |
| nsp7 | cofactor with nsp12; forming the hexadecameric complex with nsp8; exhibiting primer-independent RNA polymerase activity | (649−651) |
| nsp8 | cofactor with nsp12; forming the hexadecameric complex with nsp7; primase | (649), (650), (652) |
| nsp9 | RNA binding; enhances dimerization with diverse modes; interacts with nsp8; probably involved in viral RNA replication | (653−655) |
| nsp10 | cofactor for the N7-guanine-methyltransferase/exoribonuclease activities (nsp14) and for the 2′-O-methyltransferase activity (nsp16) | (656−659) |
| nsp11 | dispensable for viral replication in cultured cells; intrinsically disordered protein | (660), (661) |
| nsp12 | replication enzyme (RNA-dependent RNA polymerase) | (649,662−664) |
| nsp13 | RNA helicase activity; RNA 5′ triphosphatase; blocking the IFN pathway | (636), (665−667) |
| nsp14 | exoribonuclease activity; N7-methyltransferase activity | (559), (668−671) |
| nsp15 | viral endoribonuclease activity; evasion of dsRNA sensors | (672−674) |
| nsp16 | 2′-O-methyltransferase activity; regulating host immunity response; RNA cap formation | (657), (658), (675−678) |
a
Abbreviations: DMV, double-membrane vesicle; IFN, interferon; 3CLpro, 3C-like protease; Mpro, main protease.