Inhibition of mitochondrial pathway of apoptosis by poxvirus proteins

Previous studies have shown that mitochondria play a central role in the primary host defense mechanisms against numerous pathogens. These organelles are involved in the intrinsic pathway of apoptosis, which is one of the earliest responses to viral infection. The intrinsic pathway is tightly controlled by cellular Bcl-2 family proteins, which maintain the integrity with the outer mitochondrial membrane. Viruses have evolved multiple strategies to modulate apoptosis for their own purposes. Recent studies have discovered proteins encoded by the poxviruses, such as F1L, N1L, M11L, FPV039, ORF125, DPV022, and SPPV14, which have got a similar structure and/or functions as Bcl-2 family members. Newly identified poxviral proteins localize in mitochondria and interact with mitochondrial proteins to regulate cellular response. They are able to block the intrinsic pathway of apoptosis, and thereby allow the virus to replicate before its host cell dies.