ORF2
Domain
The Arginine-Rich Motif (ARM) acts as a nuclear localization signal that drives the nuclear translocation of isoform capsid protein. This motif has also been linked to the inhibition of host IRF3 phosphorylation.
Function
Isoform Secreted protein ORF2
Plays a role in the inhibition of host antibody-mediated neutralization without blocking viral cell entry.
Isoform Capsid protein
Forms an icosahedral capsid with a T=1 symmetry and a 34 nm diameter. The capsid is composed of 60 copies linked to each other. Binds to the 5' end of the genomic RNA to mediate genome encapsidation (PubMed:14671114, PubMed:15557331). Binds to heparin surface proteoglycans (HSPGs) to mediate viral entry (By similarity). Additionally, the interactions with host ASGR1 and ASGR2 facilitate viral infection of hepatocytes (By similarity). Inhibits IFN production by blocking host TBK1-induced IRF3 phosphorylation (By similarity). The nuclear form probably modulates host gene expression (By similarity).
Post-translational modifications
Pro-secreted protein ORF2
Cleaved by host protease in the N-terminus.
Isoform Secreted protein ORF2
N-glycosylated.
Isoform Capsid protein
Not N-glycosylated. The C-terminus of the capsid protein ORF2 is truncated in non-enveloped virions shedded in feces, probably due to host proteases.
Sequence Similarities
Belongs to the hepevirus capsid protein family.
Cellular localization
- Isoform Secreted protein ORF2
- Secreted
- Cotranslationally translocated into the ER (By similarity). Translation from the first AUG produces a full-length protein with a signal peptide that can direct the protein into the secretory pathway (By similarity).
- Isoform Capsid protein
- Virion
- Host cytoplasm
- Host endoplasmic reticulum
- Host Golgi apparatus
- Host cell surface
- Host nucleus
- Translation from the internal AUG codon disrupts the signal sequence, producing a cytoplasmic protein that is responsible for virion assembly (By similarity). Shuttles between cytoplasm and nucleus (By similarity). This isoform is found in quasi-enveloped virions (By similarity).
Alternative names
Pro-secreted protein ORF2, Protein ORF2, pORF2, ORF2