Crystal Structure of Human Cdk4 in Complex with a D-Type Cyclin.
Day, P.J., Cleasby, A., Tickle, I.J., O'Reilly, M., Coyle, J.E., Holding, F.P., Mcmenamin, R.L., Yon, J., Chopra, R., Lengauer, C., Jhoti, H.(2009) Proc Natl Acad Sci U S A 106: 4166
- PubMed: 19237565 
- DOI: https://doi.org/10.1073/pnas.0809645106
- Primary Citation of Related Structures:  
2W96, 2W99, 2W9F, 2W9Z - PubMed Abstract: 
The cyclin D1-cyclin-dependent kinase 4 (CDK4) complex is a key regulator of the transition through the G(1) phase of the cell cycle. Among the cyclin/CDKs, CDK4 and cyclin D1 are the most frequently activated by somatic genetic alterations in multiple tumor types. Thus, aberrant regulation of the CDK4/cyclin D1 pathway plays an essential role in oncogenesis; hence, CDK4 is a genetically validated therapeutic target. Although X-ray crystallographic structures have been determined for various CDK/cyclin complexes, CDK4/cyclin D1 has remained highly refractory to structure determination. Here, we report the crystal structure of CDK4 in complex with cyclin D1 at a resolution of 2.3 A. Although CDK4 is bound to cyclin D1 and has a phosphorylated T-loop, CDK4 is in an inactive conformation and the conformation of the heterodimer diverges from the previously known CDK/cyclin binary complexes, which suggests a unique mechanism for the process of CDK4 regulation and activation.
Organizational Affiliation: 
Astex Therapeutics Ltd., 436 Cambridge Science Park, Milton Road, Cambridge CB4 0QA, United Kingdom.