FEATURES

FAMILY

DESCRIPTION

Also known as R1A_SARS2, R1A. Multifunctional protein involved in the transcription and replication of viral RNAs. Contains the proteinases responsible for the cleavages of the polyprotein., Inhibits host translation by associating with the open head conformation of the 40S subunit (PubMed:33479166, PubMed:33080218, PubMed:32680882, PubMed:32908316). The C-terminus binds to and obstructs ribosomal mRNA entry tunnel (PubMed:33479166, PubMed:33080218, PubMed:32680882, PubMed:32908316). Thereby inhibits antiviral response triggered by innate immunity or interferons (PubMed:33080218, PubMed:32680882, PubMed:32979938). The nsp1-40S ribosome complex further induces an endonucleolytic cleavage near the 5'UTR of host mRNAs, targeting them for degradation (By similarity). Viral mRNAs less susceptible to nsp1-mediated inhibition of translation, because of their 5'-end leader sequence (PubMed:32908316, PubMed:33080218)., 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., Responsible for the cleavages located at the N-terminus of the replicase polyprotein. Participates together with nsp4 in the assembly of virally-induced cytoplasmic double-membrane vesicles necessary for viral replication (By similarity). Antagonizes innate immune induction of type I interferon by blocking the phosphorylation, dimerization and subsequent nuclear translocation of host IRF3 (PubMed:32733001). Prevents also host NF-kappa-B signaling (By similarity). In addition, PL-PRO possesses a deubiquitinating/deISGylating activity and processes both 'Lys-48'- and 'Lys-63'-linked polyubiquitin chains from cellular substrates (PubMed:32726803). Cleaves preferentially ISG15 from antiviral protein IFIH1 (MDA5), but not DDX58 (RIG-I) (PubMed:33727702). Can play a role in host ADP-ribosylation by ADP-ribose (PubMed:32578982)., Participates in the assembly of virally-induced cytoplasmic double-membrane vesicles necessary for viral replication., Cleaves the C-terminus of replicase polyprotein at 11 sites (PubMed:32321856). Recognizes substrates containing the core sequence [ILMVF]-Q-|-[SGACN] (PubMed:32198291, PubMed:32272481). Also able to bind an ADP-ribose-1''-phosphate (ADRP) (By similarity) (PubMed:32198291, PubMed:32272481)., Plays a role in the initial induction of autophagosomes from host reticulum endoplasmic (By similarity). Later, limits the expansion of these phagosomes that are no longer able to deliver viral components to lysosomes (By similarity). Binds to host TBK1 without affecting TBK1 phosphorylation; the interaction with TBK1 decreases IRF3 phosphorylation, which leads to reduced IFN-beta production (PubMed:32979938)., Plays a role in viral RNA synthesis (PubMed:32358203, PubMed:32277040, PubMed:32438371, PubMed:32526208). 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 (By similarity)., Plays a role in viral RNA synthesis (PubMed:32358203, PubMed:32277040, PubMed:32438371, PubMed:32526208). 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 (By similarity). Interacts with ribosome signal recognition particle RNA (SRP) (PubMed:33080218). Together with NSP9, suppress protein integration into the cell membrane, thereby disrupting host immune defenses (PubMed:33080218)., May participate in viral replication by acting as a ssRNA-binding protein (By similarity). Interacts with ribosome signal recognition particle RNA (SRP) (PubMed:33080218). Together with NSP9, suppress protein integration into the cell membrane, thereby disrupting host immune defenses (PubMed:33080218)., Plays a pi Interacts with host PHB and PHB2.

EXTERNAL LINKS

R1A

Replicase polyprotein 1a

R1A

Molecular Synopsis