Cyclins

Cyclins are proteins that play a key role in controlling the cell cycle . They are able to form complexes with cyclin-dependent kinases (CDKs) and to activate their kinase function . Since the cycline concentration, in contrast to the concentration of CDKs, is regulated in a cell cycle-dependent manner, these proteins also function as regulators of the cyclin-dependent kinases.

Cyclin expression during the cell cycle: red: cyclin D, green: cyclin E, blue: cyclin A, yellow: cyclin B

function

Cyclins play a role in different parts of the cell cycle through the activation of various cyclin-dependent kinases and an associated phosphorylation of various substrates. Cyclin D is present in fluctuating concentrations throughout the cell cycle. The transition from G ₁ phase to the S phase by cyclin E influenced. An increasing concentration of cyclin A leads the cell into the G ₂ phase, while cyclin B is essential for the start of mitosis . In addition, some so-called "orphan cyclins" are known for which no associated cyclin-dependent kinase has yet been found.

For the discovery of cyclins and cyclin-dependent kinases as key factors in the regulation of the cell cycle in 2001 received Leland H. Hartwell , Tim Hunt and Paul M. Nurse the Nobel Prize in Physiology or Medicine .

Individual evidence

1. ^ U. Galderisi, FP Jori, A. Giordano: Cell cycle regulation and neural differentiation. In: Oncogene. Volume 22, Number 33, August 2003, pp. 5208-5219, doi : 10.1038 / sj.onc.1206558 . PMID 12910258 (Review).
2. ^ The Nobel Prize in Physiology or Medicine 2001 . The Nobel Foundation. Retrieved January 23, 2010.