Inhibition of host mitotic exit by virus (kw:KW-1098)

Several viruses have evolved strategies to inhibit the cell cycle during mitosis, sometimes leading to cell apoptosis. The host cell is able to enter mitosis but not exit properly. Among these viruses, the chicken anemia virus apoptin inhibits the host anaphase promoting complex/cyclosome (APC/C),an ubiquitin ligase with major roles in cell cycle regulation. Apoptin associates with APC/C subunit APC1 and prevents mitosis progression. Adenovirus E4orf4 instead associates with host PP2A phosphatase, leading to both mitotic arrest and apoptosis. The association between E4orf4 and PP2A supposedly affect APC/C phosphorylation state leading to its inactivation. The TAX protein from HTLV-1 activates APC/C ahead of schedule in the S-phase and later blocks mitosis progression by interacting with subunit APC3 and PAC/C associated protein CDC20. ICP0 from HSV1 induces degradation of CENP-A and CENP-C, host proteins important for mitotic progression and chromosome segregation. This degradation prevents chromosome segregation.