Identification of human cyclin-dependent kinase 8, a putative protein kinase partner for cyclin C.
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Tassan JP, Jaquenoud M, Leopold P, Schultz SJ, Nigg EA
Identification of human cyclin-dependent kinase 8, a putative protein kinase partner for cyclin C.
Proc Natl Acad Sci U S A. 1995 Sep 12;92(19):8871-5.
- PubMed ID
- 7568034 [ View in PubMed]
- Abstract
Metazoan cyclin C was originally isolated by virtue of its ability to rescue Saccharomyces cerevisiae cells deficient in G1 cyclin function. This suggested that cyclin C might play a role in cell cycle control, but progress toward understanding the function of this cyclin has been hampered by the lack of information on a potential kinase partner. Here we report the identification of a human protein kinase, K35 [cyclin-dependent kinase 8 (CDK8)], that is likely to be a physiological partner of cyclin C. A specific interaction between K35 and cyclin C could be demonstrated after translation of CDKs and cyclins in vitro. Furthermore, cyclin C could be detected in K35 immunoprecipitates prepared from HeLa cells, indicating that the two proteins form a complex also in vivo. The K35-cyclin C complex is structurally related to SRB10-SRB11, a CDK-cyclin pair recently shown to be part of the RNA polymerase II holoenzyme of S. cerevisiae. Hence, we propose that human K35(CDK8)-cyclin C might be functionally associated with the mammalian transcription apparatus, perhaps involved in relaying growth-regulatory signals.