Component of the viral envelope that plays a central role in virus morphogenesis and assembly. It is sufficient to form virus-like particles. Seems to be important for creating the membrane curvature needed to acquire the rounded, stable and infectious particle phenotype. Acts as a viroporin, inducing the formation of hydrophilic pores in cellular membranes. Also induces apoptosis. Plays a central role in virus morphogenesis and assembly. Acts as a viroporin and self-assembles in host membranes forming pentameric protein-lipid pores that allow ion transport. Also plays a role in the induction of apoptosis. Homopentamer. Interacts with membrane protein M in the budding compartment of the host cell, which is located between endoplasmic reticulum and the Golgi complex. Interacts with Nucleoprotein. The cytoplasmic tail functions as a Golgi complex-targeting signal. Belongs to the betacoronaviruses E protein family.