A cyclin-dependent kinase complex (abbreviated cdkc, also called cyclin-CDK) is a protein complex formed by the association of cyclin with cyclin-dependent kinase. These complexes are able to phosphorylate other compounds under consumption of ATP, and are thereby involved in the regulation of the cell cycle. Depending on the type of cyclin attached to CDK, it has a different function. These serve as markers in each phase which are integral for the correct sequence of events, as well as facilitating the transition to the next phase.
There are three classes of cdkc depending on the phase of the cell cycle.