SGCG and infection: Importantly, the virion envelope is covered on its surface by the attachment glycoprotein G, which may be dispensable for infection in some cells (34–36), the fusion F glycoprotein which is a type-I integral membrane protein that binds nucleolin for cell infection (37, 38), and the transmembrane protein SH, which forms a viroporin that transports cationic ions (39, 40).