T-loop phosphorylation stabilizes the CDK7-cyclin H-MAT1 complex in vivo and regulates its CTD kinase activity Journal Article
| Authors: | Larochelle, S.; Chen, J.; Knights, R.; Pandur, J.; Morcillo, P.; Erdjument-Bromage, H.; Tempst, P.; Suter, B.; Fisher, R. P. |
| Article Title: | T-loop phosphorylation stabilizes the CDK7-cyclin H-MAT1 complex in vivo and regulates its CTD kinase activity |
| Abstract: | Cyclin-dependent kinase (CDK)7-cyclin H, the CDK-activating kinase (CAK) and TFIIH-associated kinase in metazoans can be activated in vitro through T-loop phosphorylation or binding to the RING finger protein MAT1. Although the two mechanisms can operate independently, we show that in a physiological setting, MAT1 binding and T-loop phosphorylation cooperate to stabilize the CAK complex of Drosophila. CDK7 forms a stable complex with cyclin H and MAT1 in vivo only when phosphorylated on either one of two residues (Ser164 or Thr170) in its T-loop. Mutation of both phosphorylation sites causes temperature-dependent dissociation of CDK7 complexes and lethality. Furthermore, phosphorylation of Thr170 greatly stimulates the activity of the CDKT-cyclin H-MAT1 complex towards the C-terminal domain of RNA polymerase II without significantly affecting activity towards CDK2. Remarkably, the substrate-specific increase in activity caused by T-loop phosphorylation is due entirely to accelerated enzyme turnover. Thus phosphorylation on Thr170 could provide a mechanism to augment CTD phosphorylation by TFIIH-associated CDKT, and thereby regulate transcription. |
| Keywords: | unclassified drug; gene mutation; nonhuman; animals; cell cycle; complex formation; protein kinases; carboxy terminal sequence; protein binding; protein stability; transcription factor; drosophila; genetic transcription; enzyme activity; phosphorylation; amino acid sequence; molecular sequence data; kinetics; protein-serine-threonine kinases; nucleotide sequence; substrate specificity; threonine; cycline; cyclin-dependent kinases; cyclins; cyclin dependent kinase; rna polymerase ii; dissociation; cyclin-dependent kinase; cyclin dependent kinase 7; cyclin h; transcription factor iih; enzyme metabolism; ring finger protein; temperature dependence; tfiih; priority journal; article; biopolymers; cak; protein mat 1 |
| Journal Title: | EMBO Journal |
| Volume: | 20 |
| Issue: | 14 |
| ISSN: | 0261-4189 |
| Publisher: | Wiley Blackwell |
| Date Published: | 2001-07-16 |
| Start Page: | 3749 |
| End Page: | 3759 |
| Language: | English |
| DOI: | 10.1093/emboj/20.14.3749 |
| PUBMED: | 11447116 |
| PROVIDER: | scopus |
| PMCID: | PMC125544 |
| DOI/URL: | |
| Notes: | Export Date: 21 May 2015 -- Source: Scopus |
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10Morcillo -
28
Fisher -
10
Larochelle -
324Tempst -
3
Knights
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