Cyclins

Cyclins
Cyclin is a type of protein that expresses, accumulates, and decomposes in a cell
cycle, and it interacts with cyclin-dependent kinases to affect cell cycle function.
Cyclin has involved in cell cycle-regulated proteins, and its concentration is cyclic and
cyclical in the cell cycle. Depending on the stage of the cell cycle, sometimes the
concentration is as high as several thousand times, and sometimes it drops to zero.
As a regulatory subunit, cyclin binds to and activates cyclin-dependent protein
kinases.
Different cyclins are expressed in different periods in the cell cycle. In mammalian
cells, cyclin A begins to express and gradually accumulate in the early G1 phase,
reaching the G1/S junction, and the content reaches the maximum and remains in
the G2/M phase. Cyclin B is expressed from the late G1 phase and gradually
accumulates. It reaches the maximum in the late G2 phase and maintains to the
mid-stage of the M phase, and then rapidly degrades. Cyclin D, which is a G1 phase
cyclin, is continuously expressed in the cell cycle, while cyclin E begins to express and
gradually accumulate in the late M phase and early G1 phase, reaching the maximum
in the late G1 phase, and then gradually reaching its maximum content, declining
until the late G2 phase. Cyclin plays an important role in the regulation of the cell
cycle. Studying the mechanism of cyclins has great significance for the treatment of
cancer.