CDK6

CDK6
Name	Cyclin-dependent kinase 6
Other names	Cdk6
Family	Cyclin-dependent kinases
Organism	Homo sapiens
Gene	CDK6

CDK6 is a serine/threonine protein kinase that participates in regulation of cell cycle progression, differentiation, and transcriptional programs. Discovered through studies of cell cycle control, it is mechanistically linked to cyclin partners and is implicated in oncogenesis, hematopoiesis, and development. Studies across molecular biology, oncology, and pharmacology have characterized its structure, regulatory interactions, and potential as a therapeutic target.

Structure and regulation

The kinase domain of CDK6 adopts the canonical bilobal fold seen in many kinases, analogous to structures resolved in studies of Protein Data Bank, Rous sarcoma virus-related kinases, Vascular endothelial growth factor receptor 2, Epidermal growth factor receptor, and Cyclin-dependent kinase 2. Structural comparisons to kinases such as ABL1, SRC family kinases, Cyclin-dependent kinase 4, Cyclin-dependent kinase 1, and Mitogen-activated protein kinase 1 highlight conserved ATP-binding motifs, activation segment phosphorylation sites, and cyclin-binding interfaces. Regulation occurs through binding to D-type cyclins (noted in work by groups at Dana-Farber Cancer Institute, Cold Spring Harbor Laboratory, Max Planck Institute), inhibitory phosphorylation by kinases including Wee1 homolog (S. pombe), dephosphorylation by phosphatases such as Protein phosphatase 2A, and sequestration by INK4 family inhibitors characterized in studies at University of Cambridge, Harvard Medical School, and Stanford University. Ubiquitin-mediated turnover involves E3 ligases identified in screens at Broad Institute and European Molecular Biology Laboratory.

Function and role in cell cycle

CDK6 forms active holoenzymes with cyclins D1, D2, and D3, integrating mitogenic signals from receptors such as Epidermal growth factor receptor, Platelet-derived growth factor receptor, Insulin receptor, Fibroblast growth factor receptor 1 and pathways mapped by laboratories at National Institutes of Health, Salk Institute, and Johns Hopkins University. The holoenzyme phosphorylates retinoblastoma family proteins including RB1 to promote G1 to S phase transition, a process explored in classical studies at Massachusetts Institute of Technology, Princeton University, and Yale University. CDK6 also regulates transcriptional programs via interactions with transcription factors characterized in research from University of Oxford, University of Tokyo, and University of California, San Francisco. Genetic models from groups at Imperial College London and University of Pennsylvania show roles in differentiation of tissues studied in clinics at Mayo Clinic and Cleveland Clinic.

Interaction partners and signaling pathways

Proteomic surveys from EMBL-EBI, Proteomics Center at Rockefeller University, and Institute Pasteur enumerate interaction partners including cyclins D, CDK inhibitor proteins such as p16INK4a encoded by CDKN2A, transcription factors like STAT3, NF-κB, and chromatin regulators reported by teams at Broad Institute, Genentech, and Cold Spring Harbor Laboratory. CDK6 participates in crosstalk with PI3K–AKT pathway, RAS–RAF–MEK–ERK pathway, NOTCH signaling, and Wnt signaling components mapped by consortia at Wellcome Trust Sanger Institute and European Bioinformatics Institute. Interactions with tumor suppressors such as TP53 and ubiquitin pathway members including MDM2 have been described in studies from Dana-Farber Cancer Institute and Memorial Sloan Kettering Cancer Center.

Clinical significance and disease associations

Alterations in CDK6 activity have been linked to malignancies including breast cancer, mantle cell lymphoma, acute lymphoblastic leukemia, glioblastoma multiforme, and non-small cell lung carcinoma in cohort studies at MD Anderson Cancer Center, University College London Hospitals, and Karolinska Institute. Amplification and overexpression patterns were reported in genomic surveys by The Cancer Genome Atlas and International Cancer Genome Consortium. Germline and somatic contexts studied by National Cancer Institute investigators relate CDK6 to proliferative disorders, resistance to targeted therapies reported at Memorial Sloan Kettering Cancer Center, and adverse prognosis in subsets analyzed at Royal Marsden Hospital. Beyond oncology, roles in hematopoietic disorders investigated at St. Jude Children's Research Hospital and Children's Hospital of Philadelphia connect CDK6 function to anemia, thrombocytopenia, and regenerative medicine outcomes examined at Karolinska University Hospital.

Inhibitors and therapeutic targeting

Small-molecule inhibitors selective for the CDK4/6 axis, developed by pharmaceutical efforts at Pfizer, Novartis, AstraZeneca, Eli Lilly and Company, and Bristol-Myers Squibb, include agents tested in clinical trials coordinated by European Medicines Agency, U.S. Food and Drug Administration, and cooperative groups such as European Organisation for Research and Treatment of Cancer. Approved compounds evaluated in trials at MD Anderson Cancer Center and Memorial Sloan Kettering Cancer Center demonstrated efficacy in hormone receptor-positive breast cancer cohorts. Resistance mechanisms involving compensatory signaling through PI3K, Cyclin E1, and alterations reported by consortia at Stand Up To Cancer have guided combination strategies with inhibitors targeting mTOR, HER2, and MEK tested in multicenter studies at Mayo Clinic and Vanderbilt University Medical Center.

Experimental models and research tools

Experimental approaches include CRISPR screens developed at Broad Institute, conditional knockout mice from labs at Jackson Laboratory, patient-derived xenografts maintained at The Jackson Laboratory and European Molecular Biology Laboratory, and cell line models cataloged by ATCC and DSMZ. Structural studies used facilities at Argonne National Laboratory and Diamond Light Source, while high-throughput assays were performed at Scripps Research Institute and Riken Institute. Antibodies, recombinant proteins, and chemical probes are distributed by vendors linked to repositories at Addgene, Coriell Institute for Medical Research, and NCI-60 resources, facilitating translational studies at Fred Hutchinson Cancer Research Center and University of Toronto.

Category:Kinases