1.A.14.3.12
Viroporin, pUS21, of 243 aas and 8 TMSs.  It modulates calcium ion homeostasis and protects cells against apoptosis (Luganini et al. 2018).  pUS21 of human cytomegalovirus (HCMV) constitutes a TMBIM-derived viroporin that may contribute to HCMV's overall strategy to counteract apoptosis of infected cells (Luganini et al. 2023).  US21, one of the 10 US12 genes (US12-US21), is a descendant of a captured cellular transmembrane BAX inhibitor motif-containing gene. It encodes a 7 TMS endoplasmic reticulum (ER)-resident viroporin (pUS21) capable of reducing the Ca²⁺ content of ER stores, which, in turn, protects cells against apoptosis. The US21 protein is a viral regulator of cell migration and adhesion through mechanisms involving its calcium channel activity (Luganini et al. 2023).  US21 viroporin of human cytomegalovirus stimulates cell migration and adhesion (Luganini et al. 2023).