CDKs CDK7 cyclin

CDK7/cyclin H were shown to be identical to the CDK-activating protein kinase CAK. CAK is ascribed an important role in the regulation of the cell cycle (see 14.2.1). The fimctional importance of this identity is not yet fully imderstood. 

Fisher RP, Morgan DO (1994) Anovel cyclin associates with M015/CDK7 to form the CDK-activating kinase. Cell 78(4) 713-724... 

Fig. 12.9 Indirect control of transcription by cyclin-Cdks involves interactions of transcription fector E2F with the tumour suppressors p53 and pRB. Cyclin D- and cyclin E-associated kinases phosphorylate pRB and lift the biock of transcription. Appropriate changes of the phosphorylation state of p53 improve the specificity of DNA binding arxj promote the transcriptional activity of E2F. This effect is amplified by phosphorylation of p53 by cyiin A-Cdkl. (Cyclin H/Cdk7/CAK and cyclin C/Cdk8 complexes can activate transcription directly, by association with the basal transcription machinery and phosphorylation of RNA polymerase II, Pol II see also Chapters 9 and 10).

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