What are cyclins?and How do cyclins oscillate? Solution Cyclines are group of protein that control the progression of cell in cell cycle by activating cycline dependent kinase. Each cycline associates with one or two CDK. And cycline - CDK complex results in activation of active sites. Some studies suggest that cell cycle is triggered by an oscillator present in midst of cyclin - CDK complex. Cyclins in presence of sufficient growth factor of CDK is capable of self organisation in the form of oscillations. The oscillations corresponds to sequential activation various CDK cyclin complex that control cell cycle.the change from cell quiescence to cell proliferation corresponds to transition from a stable state to oscillations state of CDK..