title: Direct activation of cyclin-dependent kinase 2 by human papillomavirus E7.
abstract: Addition of human papillomavirus (HPV) E7 CDK2/cyclin A or CDK2/cyclin E, purified from either insect cells or bacteria, dramatically upregulates histone H1 kinase activity. Activation is substrate specific, with a smaller effect noted for retinoblastoma protein (Rb). The CDK2 stimulatory activity is equivalent in high-risk (HPV type 16 [HPV16] and HPV31) and low-risk (HPV6b) E7. Mutational analyses of HPV16 E7 indicate that the major activity resides in amino acids 9 to 38, spanning CR1 and CR2, and does not require casein kinase II or Rb-binding domain functions. Synthetic peptides spanning HPV16 amino acid residues 9 to 38 also activate CDK2. Peptides containing this sequence that carry biotin on the carboxy terminus, as well as a photoactivated cross-linking group (benzophenone), also activate the complex and covalently associate with the CDK2/cyclin A complex in a specific manner requiring UV. Cross-linking studies that use protein monomers detect association of the E7 peptides with cyclin A but not CDK2. Together, our results indicate a novel mechanism whereby E7 promotes HPV replication by directly altering CDK2 activity and substrate specificity.
authors.affiliation: Genomics-ID, Kalamazoo, Michigan 49006, USA.
authors.forename: Wanxia
authors.initials: W
authors.lastname: He
authors.forename: Doug
authors.initials: D
authors.lastname: Staples
authors.forename: Clark
authors.initials: C
authors.lastname: Smith
authors.forename: Chris
authors.initials: C
authors.lastname: Fisher
mesh_terms: D000595:Amino Acid Sequence; D042846:CDC2-CDC28 Kinases; D019925:Cyclin A / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004789:Enzyme Activation; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000502:physiology*; D050725:Papillomavirus E7 Proteins; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D013379:Substrate Specificity; D014779:Virus Replication
chemical_list: D019925:Cyclin A; C085208:E7 protein, Human papillomavirus 6b; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; C059731:oncogene protein E7, Human papillomavirus type 16; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases