A cytomegalovirus-encoded inhibitor of apoptosis that suppresses caspase-8 activation

A Skaletskaya, LM Bartle… - Proceedings of the …, 2001 - National Acad Sciences
A Skaletskaya, LM Bartle, T Chittenden, AL McCormick, ES Mocarski, VS Goldmacher
Proceedings of the National Academy of Sciences, 2001National Acad Sciences
We have identified a human cytomegalovirus cell-death suppressor, denoted vICA, encoded
by the viral UL36 gene. vICA inhibits Fas-mediated apoptosis by binding to the pro-domain
of caspase-8 and preventing its activation. vICA does not share significant sequence
homology with FLIPs or other known suppressors of apoptosis, suggesting that this protein
represents a new class of cell-death suppressors. Notably, resistance to Fas-mediated
apoptosis is delayed in fibroblasts infected with viruses that encode mutant vICA, suggesting …
We have identified a human cytomegalovirus cell-death suppressor, denoted vICA, encoded by the viral UL36 gene. vICA inhibits Fas-mediated apoptosis by binding to the pro-domain of caspase-8 and preventing its activation. vICA does not share significant sequence homology with FLIPs or other known suppressors of apoptosis, suggesting that this protein represents a new class of cell-death suppressors. Notably, resistance to Fas-mediated apoptosis is delayed in fibroblasts infected with viruses that encode mutant vICA, suggesting that vICA suppresses death-receptor-induced cell death in the context of viral infection. Although vICA is dispensable for viral replication in vitro, the common targeting of caspase-8 activation by diverse herpesviruses argues for an important role for this antiapoptotic mechanism in the pathogenesis of viral infection in the host, most likely in avoiding immune clearance by cytotoxic lymphocytes and natural killer cells.
National Acad Sciences