Cyclin-dependent kinase 1Cyclin-dependent kinase 1 also known as CDK1 or cell division cycle protein 2 homolog is a highly conserved protein that functions as a serine/threonine protein kinase, and is a key player in cell cycle regulation. It has been highly studied in the budding yeast S. cerevisiae, and the fission yeast S. pombe, where it is encoded by genes cdc28 and cdc2, respectively. With its cyclin partners, Cdk1 forms complexes that phosphorylate a variety of target substrates (over 75 have been identified in budding yeast); phosphorylation of these proteins leads to cell cycle progression.
Cyclin-dependent kinase 7Cyclin-dependent kinase 7, or cell division protein kinase 7, is an enzyme that in humans is encoded by the CDK7 gene. The protein encoded by this gene is a member of the cyclin-dependent protein kinase (CDK) family. CDK family members are highly similar to the gene products of Saccharomyces cerevisiae cdc28, and Schizosaccharomyces pombe cdc2, and are known to be important regulators of cell cycle progression. This protein forms a trimeric complex with cyclin H and MAT1, which functions as a Cdk-activating kinase (CAK).
Kinase dépendante des cyclinesvignette|350px|Schéma du cycle cellulaire. Cercle extérieur: I=Interphase, M=Mitose; cercle intérieur: M=Mitose et cytocinèse; G1=Phase G1; S=Phase S; G2=Phase G2. La durée de la mitose par rapport aux autres phases du cycle cellulaire est exagérée dans ce diagramme Les kinases dépendantes des cyclines (en anglais, cyclin-dependent kinase ou CDK) sont une famille de protéines kinases qui jouent un rôle majeur dans la régulation du cycle cellulaire.
Cyclin-dependent kinase 2Cyclin-dependent kinase 2, also known as cell division protein kinase 2, or Cdk2, is an enzyme that in humans is encoded by the CDK2 gene. The protein encoded by this gene is a member of the cyclin-dependent kinase family of Ser/Thr protein kinases. This protein kinase is highly similar to the gene products of S. cerevisiae cdc28, and S. pombe cdc2, also known as Cdk1 in humans. It is a catalytic subunit of the cyclin-dependent kinase complex, whose activity is restricted to the G1-S phase of the cell cycle, where cells make proteins necessary for mitosis and replicate their DNA.
CDK4La CDK4 est une kinase dépendante des cyclines. Son gène est le CDK4 situé sur le chromosome 12 humain. Le complexe Cdk4-cycline D phosphoryle la pRB, engendrant un changement conformationnel la rendant inactif, libérant E2F et permettant à la cellule de progresser dans le cycle cellulaire. Cette protéine joue un rôle dans la prolifération cellulaire, notamment dans les cancers, constituant une cible thérapeutique. Le palbociclib et le ribociclib sont des inhibiteurs des CDK4 et CDK6 efficaces dans certains cancers du sein.
Cyclin-dependent kinase 6Cell division protein kinase 6 (CDK6) is an enzyme encoded by the CDK6 gene. It is regulated by cyclins, more specifically by Cyclin D proteins and Cyclin-dependent kinase inhibitor proteins. The protein encoded by this gene is a member of the cyclin-dependent kinase, (CDK) family, which includes CDK4. CDK family members are highly similar to the gene products of Saccharomyces cerevisiae cdc28, and Schizosaccharomyces pombe cdc2, and are known to be important regulators of cell cycle progression in the point of regulation named R or restriction point.
Restriction pointThe restriction point (R), also known as the Start or G1/S checkpoint, is a cell cycle checkpoint in the G1 phase of the animal cell cycle at which the cell becomes "committed" to the cell cycle, and after which extracellular signals are no longer required to stimulate proliferation. The defining biochemical feature of the restriction point is the activation of G1/S- and S-phase cyclin-CDK complexes, which in turn phosphorylate proteins that initiate DNA replication, centrosome duplication, and other early cell cycle events.
Phosphorylationthumb|chaîne latérale de sérine phosphorylée. Les atomes d'oxygène sont en rouge, ceux de phosphore, en orange, le carbone en gris et l'azote en bleu. Les atomes d'hydrogène ne sont pas représentés. La phosphorylation est l'addition d'un groupe phosphate (un phosphoryl PO32− plus précisément) qui est transféré à une protéine ou à une petite molécule, tel le glucose, l'adénine ou les glycérolipides. Son rôle prééminent en biochimie est le sujet de très nombreuses recherches (la base de données MEDLINE signale plus de articles sur ce sujet, pour la plupart concernant la phosphorylation des protéines).
Cyclin-dependent kinase complexA cyclin-dependent kinase complex (CDKC, cyclin-CDK) is a protein complex formed by the association of an inactive catalytic subunit of a protein kinase, cyclin-dependent kinase (CDK), with a regulatory subunit, cyclin. Once cyclin-dependent kinases bind to cyclin, the formed complex is in an activated state. Substrate specificity of the activated complex is mainly established by the associated cyclin within the complex. Activity of CDKCs is controlled by phosphorylation of target proteins, as well as binding of inhibitory proteins.
Inhibiteur de CDKA cyclin-dependent kinase inhibitor protein (also known as CKIs, CDIs, or CDKIs) is a protein which inhibits the enzyme cyclin-dependent kinase (CDK) and Cyclin activity by stopping the cell cycle if there are unfavorable conditions, therefore, acting as tumor suppressors. Cell cycle progression is stopped by Cyclin-dependent kinase inhibitor protein at the G1 phase. CKIs are vital proteins within the control system that point out whether the process of DNA synthesis, mitosis, and cytokines control one another.
Retinoblastoma-like protein 1Retinoblastoma-like 1 (p107), also known as RBL1, is a protein that in humans is encoded by the RBL1 gene. The protein encoded by this gene is similar in sequence and possibly function to the product of the retinoblastoma 1 (RB1) gene. The RB1 gene product is a tumor suppressor protein that appears to be involved in cell cycle regulation, as it is phosphorylated in the S to M phase transition and is dephosphorylated in the G1 phase of the cell cycle.
