Table 4.
Characteristics of ORF3 homologs in coronaviruses.
| CoV | ORF | Length (aa) |
Function | Subcellular localization |
|---|---|---|---|---|
| SARS | ORF3a | 274 | Ion channel (Lu et al., 2006) and pro apoptotic (Chan et al., 2009) activities | Cytoplasm, plasma membrane (Tan et al., 2004) and Golgi apparatus (Yu et al., 2004) |
| TGEV | ORF3b | 244 | Viral pathogenicity (Wesley and Woods, 2001) | Unknown |
| PEDV | ORF3 | 224 | Ion channel activity (Wang et al., 2012), prolongs S phase and facilitates vesicle formation (Ye et al., 2015) | Cytoplasm and punctuate vesicle-like structures in the cytoplasm (Ye et al., 2015) and unpublished data) |
| HCoV-229E | ORF4a | 133 | Ion channel activity and acts as viroporin (Zhang et al., 2014) | Endoplasmic reticulum/Golgi intermediate compartment (Zhang et al., 2014) |
| HCoV-NL63 | ORF3 | 225 | Structural viral protein (Muller et al., 2010) | Endoplasmic reticulum/Golgi intermediate compartment (Muller et al., 2010) |