Putative adenovirus Bcl-2 homolog that inhibits apoptosis induced by TNF or FAS pathways, as well as p53-mediated apoptosis. Without E1B 19K function, virus production is compromised because of premature death of host cell. Interacts with Bax protein in cell lysates (By similarity). Associated with the plasma and nuclear membranes, and with the insoluble nuclear lamina. Belongs to the adenoviridae E1B 19 kDa protein family.