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. Homooligomer. Interacts with the M membrane protein in the budding compartment of the host cell, which is located between endoplasmic reticulum and the Golgi complex. The cytoplasmic tails of both proteins are important for this function. Interacts with Nucleoprotein. The cytoplasmic tail functions as a Golgi complex-targeting signal. Belongs to the gammacoronaviruses E protein family.