title: Human cyclin K, a novel RNA polymerase II-associated cyclin possessing both carboxy-terminal domain kinase and Cdk-activating kinase activity.
abstract: The gene coding for human cyclin K was isolated as a CPR (cell-cycle progression restoration) gene by virtue of its ability to impart a Far- phenotype to the budding yeast Saccharomyces cerevisiae and to rescue the lethality of a deletion of the G1 cyclin genes CLN1, CLN2, and CLN3. The cyclin K gene encodes a 357-amino-acid protein most closely related to human cyclins C and H, which have been proposed to play a role in regulating basal transcription through their association with and activation of cyclin-dependent kinases (Cdks) that phosphorylate the carboxyl-terminal domain (CTD) of the large subunit of RNA polymerase II (RNAP II). Murine and Drosophila melanogaster homologs of cyclin K have also been identified. Cyclin K mRNA is ubiquitously expressed in adult mouse and human tissues, but is most abundant in the developing germ cells of the adult testis and ovaries. Cyclin K is associated with potent CTD kinase and Cdk kinase (CAK) activity in vitro and coimmunoprecipitates with the large subunit of RNAP II. Thus, cyclin K represents a new member of the "transcription" cyclin family which may play a dual role in regulating Cdk and RNAP II activity.
authors.affiliation: Verna and Marrs McLean Department of Biochemistry and Department of Molecular and Human Genetics, Howard Hughes Medical Institute, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Edwards
authors.forename: C
authors.initials: C
authors.lastname: Wong
authors.forename: S J
authors.initials: SJ
authors.lastname: Elledge
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002460:Cell Line; D003067:Coenzymes / Q000235:genetics / Q000378:metabolism*; D056850:Cyclin-Dependent Kinase 8; D018844:Cyclin-Dependent Kinases; D016213:Cyclins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D016193:G1 Phase; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007313:Insecta; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010641:Phenotype; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D000091346:Tripeptidyl-Peptidase 1; D014452:Ubiquitins / Q000378:metabolism; D000095043:Cyclin-Dependent Kinase-Activating Kinase
chemical_list: C113028:CCNK protein, human; D003067:Coenzymes; D016213:Cyclins; D029721:Drosophila Proteins; D029701:Saccharomyces cerevisiae Proteins; C000717268:Tpp1 protein, mouse; D000091346:Tripeptidyl-Peptidase 1; D014452:Ubiquitins; D005982:Glutathione Transferase; D011494:Protein Kinases; C060137:carboxy-terminal domain kinase; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; C095686:CDK8 protein, human; C498308:Cdk8 protein, Drosophila; D056850:Cyclin-Dependent Kinase 8; D018844:Cyclin-Dependent Kinases; C498309:SSN3 protein, S cerevisiae; D012319:RNA Polymerase II; D000095043:Cyclin-Dependent Kinase-Activating Kinase