Coronavirus 2019 disease (COVID-19), formerly known as Acute Respiratory Illness 2019-nCoV, is an infectious disease caused by SARS-CoV-2, a virus closely related to the SARS virus. The envelope protein, or protein E, is a small 100-residue polypeptide that contains at least one helical transmembrane domain α and a group of 2-3 juxtamembrane cysteines. It is involved in several processes of the virus life cycle, such as assembly, budding, envelope formation and pathogenesis. Protein E has membrane permeabilizing activity, which may justify in vitro inhibition of the ion channel activity of some synthetic coronavirus E proteins, as well as viral replication. It acts as a viroporin and self-assembles in host membranes forming pentameric protein-lipid pores that allow ion transport. It also plays a role in the induction of apoptosis, activates the NLRP3 inflammasome of the host resulting in overproduction of IL-1 beta.