Inhibition of host apoptosis by viral BCL2-like protein

Cellular Bcl-2 family proteins regulate critical steps in programmed cell death pathway by modulating mitochondrial permeability and function. They can be divided on two distinct groups, anti-apoptotic members such as Bcl-2 and Bcl-Xl that prevent cell death and pro-apoptotic elements like Bax and Bak that promote apoptosis.

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Bcl-2 family proteins are also encoded by several large DNA viruses, including all known gamma herpesviruses, adenoviruses, and several other unrelated viruses. Viral Bcl-2 proteins can prevent cell death but often escape cellular regulatory mechanisms that govern their cellular counterparts. Compared to the cellular Bcl-2, viral Bcl-2 members are shorter and are often devoid of a membrane-anchored domain. Even with low level of homology with Bcl-2 such as adenovirus E1B19K, all viral Bcl-2 proteins analyzed so far are able to block apoptosis.