Abstract
The human CDK-activating kinase (CAK), composed of CDK7, cyclin H, and MAT1, is involved in the control of transcription initiation and the cell cycle. Because of these activities, it has been identified as a promising target for cancer chemotherapy. A number of CDK7 inhibitors have entered clinical trials, among them ICEC0942 (also known as CT7001). Structural information can aid in improving the affinity and specificity of such drugs or drug candidates, reducing side effects in patients. Here, we have determined the structure of the human CAK in complex with ICEC0942 at 2.5 Å-resolution using cryogenic electron microscopy. Our structure reveals conformational differences of ICEC0942 compared with previous X-ray crystal structures of the CDK2-bound complex, and highlights the critical ability of cryogenic electron microscopy to resolve structures of drug-bound protein complexes without the need to crystalize the protein target.
Highlights
The human cyclin-dependent kinase (CDK)-activating kinase (CAK) is a trimeric complex comprising CDK7 as well as cyclin H and MAT1 [1,2]
To obtain insight into the mode of binding of ICEC0942 [11] to the human CDK-activating kinase (CAK), we collected cryogenic electron microscopy (cryo-EM) data of the CAK-ICEC0942 complex using a 200-kV electron microscope equipped with a direct detector capable of electron counting, as used previously for structure determination of the CAK [20] and other small complexes [44]
Our previous cryo-EM visualization of human CAK indicated that preferred orientation is an issue with this specimen and that the orientation distribution of the complex on the grid can vary substantially, even between grids prepared using near-identical conditions
Summary
The human cyclin-dependent kinase (CDK)-activating kinase (CAK) is a trimeric complex comprising CDK7 as well as cyclin H and MAT1 [1,2]. In addition to its role in RNA polymerase II phosphorylation, the human CAK phosphorylates numerous other targets involved in transcription and the cell cycle [7], including other CDKs [1]. Because of their dual function in regulation of transcription and the cell cycle, CDK7 and the CAK are important regulators of cell growth and cell division. Deregulation of these pathways leads to human disease, including cancer, and many cancers rely on aberrantly upregulated transcription to sustain their growth and proliferation [8]. Among those clinical CDK7 inhibitors is the pyrazolopyrimidine derivative ICEC0942 ( known as CT7001) [11], which binds CDK7 noncovalently but with high affinity and selectivity for CDK7 over other CDKs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
