Table 1.

The biological roles of different PEDV proteins.

Classification	Proteins	The biological roles	References
Nonstructural proteins	Nsp1	A vital virulence factor; suppression of type I interferon and type III interferon production; reduces the early production of proinflammatory cytokine, such as TNFα, TGF-β3, IL-6, IL-15, IL-17, IL-1β	[28,67,129,185]
	Nsp3	Deubiquitinates RIG-I and STING; inhibits IFN-β and IFN-λ1 expression.	[129,186]
	Nsp4	Upregulates IL-1α, IL-1β, TNF-α, CCL2, CCL5 and CXCL8 expression.	[187]
	Nsp5	Cleaves NEMO at position 231 (Q231) and inhibits type I interferon production.	[30]
	Nsp 6	Induces autophagy through the PI3K/Akt/mTOR signaling pathway in IPEC-J2 cells.	[188]
	Nsp7, nsp8 and nsp9	Inhibits the IFN-β and IRF3 promoter activities, viral replication	[67,68,129]
	Nsp13-16	Involves in viral replication; inhibition of the type I IFN and the type III IFN; vital virulence factors.	[80,84,85,129,189,190]
Structural proteins	S	Induces neutralizing antibodies; receptor binding and membrane fusion; a vital virulence factor; S1 Spike protein induces cell apoptosis.	[119,191,192]
	E	Stimulates ER stress and up-regulates the production of IL-6 and IL-8; promotes apoptosis; inhibits the IFN promoter activities.	[95,129]
	M	Induces cell cycle arrest at the S-phase; inhibits the IFN promoter activities.	[129,193]
	N	Antagonizes IFN-β and IFN-λ Production; prolongs S-phase cell cycle; stimulates ER stress and up-regulates the production of Bcl-2 and IL-8.	[194,195]
Accessory protein	ORF3	Owns ion channel activity; inhibits apoptosis and promotes autophagy; causes endoplasmic reticulum stress; promotes PEDV replication.	[89,98,196,197]