Protein Domain : Structural accessory protein ORF7b, betacoronavirus IPR021532

Type	Family
Description	This entry corresponds to ORF7b (also known as accessory protein 7b, NS7B, and 7b) from human SARS coronavirus (SARS-CoV) and SARS-CoV-2, which belong to the betacoronavirus B lineage (Sarbecovirus) [ ].ORF7b/NS7b from betacoronavirus in the B lineage are not related to NS7b proteins from other betacoronavirus lineages. The SARS-CoV ORF7b protein is a 44 amino acid protein which is homologous to an accessory but structural component of SARS-CoV virion. While ORF7b is packaged into virions, it is not required for the virus budding process, as gene 7 deletion viruses replicate efficiently in vitro and in vivo. Moreover, ORF7b possesses a transmembrane helical domain (TMD), between 9-29 amino acid residues, is necessary for its Golgi complex localization, as replacing it with the TMD from the human endoprotease furin results in aberrant localization [ , ].ORF7b from SARS-CoV-2 is a 43 amino acid protein localized in the membrane of the endoplasmic reticulum and it has been shown to induce apoptosis. It promotes expression of IFN-beta, TNF-alpha, and IL-6, and activation of type-I IFN signaling through IRF3 phosphorylation and to activate TNFalpha-induced apoptosis in HEK293T cells and Vero E6 cells [ , ]. These recent findings suggest a mechanism to understand pathogenicity of SARS-CoV-2 and the role of its accessory proteins in modulating host immune responses.
Short Name	NS7B_bCoV