Cyclin E Formation of Cyclin E:Cdk2 complexes Pubmed7799941 Reactome Database ID Release 4369191 Reactome, http://www.reactome.org ReactomeREACT_1683 The E-type cyclins and Cyclin Dependent Kinase 2 control the transition from G1 to S phase. Cdk2 is competent to carry out the necessary reactions only when complexed with Cyclin E. Cyclin E:Cdk2 complex