The structure and substrate specificity of human Cdk12/Cyclin K
| Authors | |
|---|---|
| Year of publication | 2014 |
| Type | Article in Periodical |
| Magazine / Source | NATURE COMMUNICATIONS |
| MU Faculty or unit | |
| Citation | |
| Web | http://www.nature.com/ncomms/2014/140324/ncomms4505/pdf/ncomms4505.pdf |
| Doi | http://dx.doi.org/10.1038/ncomms4505 |
| Field | Biochemistry |
| Keywords | RNA-POLYMERASE-II; C-TERMINAL DOMAIN; CAPPING ENZYME RECRUITMENT; CYCLIN-DEPENDENT KINASE-9; CTD CODE; P-TEFB; PROTEIN-KINASES; FISSION YEAST; CRYSTAL-STRUCTURE; IN-VIVO |
| Description | Phosphorylation of the RNA polymerase II C-terminal domain (CTD) by cyclin-dependent kinases is important for productive transcription. Here we determine the crystal structure of Cdk12/CycK and analyse its requirements for substrate recognition. Active Cdk12/CycK is arranged in an open conformation similar to that of Cdk9/CycT but different from those of cell cycle kinases. Cdk12 contains a C-terminal extension that folds onto the N- and C-terminal lobes thereby contacting the ATP ribose. The interaction is mediated by an HE motif followed by a polybasic cluster that is conserved in transcriptional CDKs. Cdk12/CycK showed the highest activity on a CTD substrate prephosphorylated at position Ser7, whereas the common Lys7 substitution was not recognized. Flavopiridol is most potent towards Cdk12 but was still 10-fold more potent towards Cdk9. T-loop phosphorylation of Cdk12 required coexpression with a Cdk-activating kinase. These results suggest the regulation of Pol II elongation by a relay of transcriptionally active CTD kinases. |
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