title: Cdk2 as a master of S phase entry: fact or fake?
abstract: It has long been believed that Cdk2 and its activator cyclin E play essential roles in the progression of the mitotic cell cycle. However, recent studies using knockout mouse models revealed that neither Cdk2 nor cyclin E are essential in vivo. The purpose of this Perspective is to compare both Cdk2 and cyclin E knockout mice models and to discuss potential mechanisms driving the cell cycle in the absence of Cdk2 or cyclin E. Particular emphasis is placed on possible non-catalytic roles of cyclin E, the expression and activity of the second cyclin binding partner of Cdk2, cyclin A, as well as on the expression and degradation of the Cdk2 inhibitor p27Kip1 in the absence of Cdk2.
authors.affiliation: National Cancer Institute, Regulation of Cell Growth Laboratory, Frederick, Maryland 21702-1201, USA.
authors.forename: Eiman
authors.initials: E
authors.lastname: Aleem
authors.forename: Cyril
authors.initials: C
authors.lastname: Berthet
authors.forename: Philipp
authors.initials: P
authors.lastname: Kaldis
mesh_terms: D000818:Animals; D042846:CDC2-CDC28 Kinases / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D019927:Cyclin E / Q000502:physiology*; D051357:Cyclin-Dependent Kinase 2; D050760:Cyclin-Dependent Kinase Inhibitor p27; D051379:Mice; D018345:Mice, Knockout; D016196:S Phase / Q000502:physiology*; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
chemical_list: C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D019927:Cyclin E; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D042846:CDC2-CDC28 Kinases; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2