HPV Cancer

P53 and Rb are tumor suppressors P53 controlled and regulated depending on needs of cycle P21 inhibits action of cyclin and CDK G1: S Checkpoint Rb release e2f, phosphorylated by kinase If p53 active, leads to transcription of p21 P21 block activity of cyclin dependent kinase Rb not phosphorylated and maintains interaction with e3f Don’t progress further in cycle If p53 degraded, lose p21 Relieves expression of CDK Phosphorylated RB, release E2F Progress into S phase p53 regulation: ubiquitin dependent proteolysis: Expression of E3 regulated expression of P53 Genome integration: E6/7 regulate cell cycle Neoplasia cancer Integration of virus into genome, direct cause Break of circular viral genome occurs in the middle of E2 E2 cut in half, not functional Can’t repress p97, constitutively active E6/7 are active When E7 of virus is present, binds to Rb instead of E2F, bypass G1 checkpoint When E6 of virus is present, recruits p53 to be ubiquinated and degraded Prevents p21 cycle Immune protection: Doesn’t lead to cytoxic t cell response Uses serum antibodies