title: [Cyclins A and B: redundancy and specificity].
abstract: Mitotic cyclins constitute a regulatory subunit of the histone H1 kinase complex. On the basis of primary structure differences, they are divided into two classes, A and B. Both classes are necessary for mitosis to occur. Cyclins A and B differ in the timing of their cellular expression and in their affinity with the various members of the cdk (cyclin-dependent kinases) family. They also have specific functions: cyclin A plays a role in DNA replication, whereas cyclin B are involved in the inhibition of the fusion of early endosomes and in the activation of cdc25 phosphatase. Cyclins A and B can contribute to the development of neoplastic disorders, either directly (inappropriate expression of the cyclin A gene caused by the hepatitis B virus in hepatocellular carcinoma, interactions between cyclin A and factors involved in the regulation of cell division), or indirectly by causing phosphorylation of oncogene products by a cdk.
authors.affiliation: Laboratoire de Cytologie Analytique et Cytogénétique Moléculaire, Université Claude Bernard, Lyon, France.
authors.forename: D
authors.initials: D
authors.lastname: Wolowiec
authors.forename: M
authors.initials: M
authors.lastname: Ffrench
mesh_terms: D016203:CDC2 Protein Kinase / Q000502:physiology; D042846:CDC2-CDC28 Kinases; D006528:Carcinoma, Hepatocellular / Q000209:etiology / Q000503:physiopathology; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D016213:Cyclins / Q000502:physiology*; D004261:DNA Replication; D006509:Hepatitis B / Q000150:complications / Q000503:physiopathology; D006801:Humans; D008113:Liver Neoplasms / Q000209:etiology / Q000503:physiopathology; D008938:Mitosis / Q000502:physiology*; D011494:Protein Kinases / Q000502:physiology; D017346:Protein Serine-Threonine Kinases; D016196:S Phase; D013539:Simian virus 40; D014412:Tumor Virus Infections / Q000503:physiopathology
chemical_list: D016213:Cyclins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases
vernacular_title: Cyclines A et B: redondance et spécificité.