1.A.99 The Infectious Bronchitis Virus Envelope Small Membrane Protein E (IBV-E) Family. 

The E protein is a 108 aa, 2 TMS protein belived to be a viroporin.  It interacts with the membrane (M) protein (Lim et al. 2001). The E protein is a component of the viral envelope that plays a central role in virus morphogenesis and assembly. It seems to be important for creating the membrane curvature needed to acquire the rounded, stable and infectious particle phenotype. The E protein acts as a viroporin, inducing the formation of hydrophilic pores in cellular membranes and mediates ER stress, thereby modulating virion release, apoptosis, viral fitness, and pathogenesis (Li et al. 2019).

This family belongs to the Viroporin-3.



Li, S., L. Yuan, G. Dai, R.A. Chen, D.X. Liu, and T.S. Fung. (2019). Regulation of the ER Stress Response by the Ion Channel Activity of the Infectious Bronchitis Coronavirus Envelope Protein Modulates Virion Release, Apoptosis, Viral Fitness, and Pathogenesis. Front Microbiol 10: 3022.

Lim, K.P., H.Y. Xu, and D.X. Liu. (2001). Physical interaction between the membrane (M) and envelope (E) proteins of the coronavirus avian infectious bronchitis virus (IBV). Adv Exp Med Biol 494: 595-602.

Pendleton, A.R. and C.E. Machamer. (2008). Generating antibodies to the gene 3 proteins of infectious bronchitis virus. Methods Mol Biol 454: 163-189.


TC#NameOrganismal TypeExample

The avian infectious bronchitis virus envelope small membrane protein E of 108 aas and 2 TMSs.  IBV E functions as a viroporin and plays a role in virus budding, possibly by altering membrane morphology at the virus assembly site (Pendleton and Machamer 2008). It also mediates ER stress and thereby modulates virion release, apoptosis, viral fitness, and pathogenesis (Li et al. 2019).

The E protein of avian infectious bronchitis virus


Small envelope membrane protein E of 65 aas and 2 TMSs

E protein of Turkey enteric coronavirus (TCoV) (TCV)


Small membrane envelope (E) protein of 95 aas and 1 or 2 TMSs

E protein of Beluga Whale coronavirus SW1