SARS-Coronavirus Nonstructural Protein 8 Products

Replicase polyprotein 1ab: Multifunctional protein involved in the transcription and replication of viral RNAs. Contains the proteinases responsible for the cleavages of the polyprotein. Host translation inhibitor nsp1: Inhibits host translation by interacting with the 40S ribosomal subunit. The nsp1-40S ribosome complex further induces an endonucleolytic cleavage near the 5'UTR of host mRNAs, targeting them for degradation. Viral mRNAs are not susceptible to nsp1-mediated endonucleolytic RNA cleavage thanks to the presence of a 5'-end leader sequence and are therefore protected from degradation. By suppressing host gene expression, nsp1 facilitates efficient viral gene expression in infected cells and evasion from host immune response. {ECO:0000269|PubMed:23035226}. Non-structural protein 2: May play a role in the modulation of host cell survival signaling pathway by interacting with host PHB and PHB2. Indeed, these two proteins play a role in maintaining the functional integrity of the mitochondria and protecting cells from various stresses. {ECO:0000269|PubMed:19640993}. Papain-like proteinase: Responsible for the cleavages located at the N-terminus of the replicase polyprotein. In addition, PL-PRO possesses a deubiquitinating/deISGylating activity and processes both 'Lys-48'- and 'Lys-63'-linked polyubiquitin chains from cellular substrates. Participates together with nsp4 in the assembly of virally-induced cytoplasmic double-membrane vesicles necessary for viral replication. Antagonizes innate immune induction of type I interferon by blocking the phosphorylation, dimerization and subsequent nuclear translocation of host IRF3. Prevents also host NF-kappa-B signaling. {ECO:0000269|PubMed:17692280, ECO:0000269|PubMed:19369340}. Non-structural protein 4: Participates in the assembly of virally-induced cytoplasmic double-membrane vesicles necessary for viral replication. {ECO:0000269|PubMed:23943763}. Proteinase 3CL-PRO: Ccleaves the C-terminus of replicase polyprotein at 11 sites. Recognizes substrates containing the core sequence [ILMVF]-Q-|-[SGACN]. Also able to bind an ADP-ribose-1''- phosphate (ADRP). {ECO:0000255|PROSITE-ProRule:PRU00772, ECO:0000269|PubMed:16271890}. Non-structural protein 6: Plays a role in the initial induction of autophagosomes from host reticulum endoplasmic. Later, limits the expansion of these phagosomes that are no longer able to deliver viral components to lysosomes. {ECO:0000269|PubMed:24991833}. Non-structural protein 7: Forms a hexadecamer with nsp8 (8 subunits of each) that may participate in viral replication by acting as a primase. Alternatively, may synthesize substantially longer products than oligonucleotide primers. {ECO:0000269|PubMed:22039154}. Non-structural protein 8: Forms a hexadecamer with nsp7 (8 subunits of each) that may participate in viral replication by acting as a primase. Alternatively, may synthesize substantially longer products than oligonucleotide primers. {ECO:0000269|PubMed:22039154}. Non-structural protein 9: May participate in viral replication by acting as a ssRNA-binding protein. {ECO:0000269|PubMed:19153232}. Non-structural protein 10: Plays a pivotal role in viral transcription by stimulating both nsp14 3'-5' exoribonuclease and nsp16 2'-O-methyltransferase activities. Therefore plays an essential role in viral mRNAs cap methylation. {ECO:0000269|PubMed:22635272}. RNA-directed RNA polymerase: Responsible for replication and transcription of the viral RNA genome. {ECO:0000269|PubMed:22791111}. Helicase: Multi-functional protein with a zinc-binding domain in N-terminus displaying RNA and DNA duplex-unwinding activities with 5' to 3' polarity. Activity of helicase is dependent on magnesium. {ECO:0000269|PubMed:12917423, ECO:0000269|PubMed:22615777}. Guanine-N7 methyltransferase: Enzyme possessing two ssRNA and dsRNA in a 3' to 5' direction and a N7-guanine methyltransferase activity. {ECO:0000269|PubMed:16549795, ECO:0000269|PubMed:20421945, ECO:0000269|PubMed:22635272}. Uridylate-specific endoribonuclease: Mn(2+)-dependent, uridylate-specific enzyme, which leaves 2'-3'-cyclic phosphates 5' to the cleaved bond. 2'-O-methyltransferase: Methyltransferase that mediates mRNA cap 2'-O-ribose methylation to the 5'-cap structure of viral mRNAs. N7-methyl guanosine cap is a prerequisite for binding of nsp16. Therefore plays an essential role in viral mRNAs cap methylation which is essential to evade immune system. {ECO:0000269|PubMed:18417574, ECO:0000269|PubMed:20421945, ECO:0000305}.