Regulates CDK7, the catalytic subunit of the CDK- activating kinase (CAK) enzymatic complex. CAK activates the cyclin-associated kinases CDK1, CDK2, CDK4 and CDK6 by threonine phosphorylation. CAK complexed to the core-TFIIH basal transcription factor activates RNA polymerase II by serine phosphorylation of the repetitive C-terminus domain (CTD) of its large subunit (POLR2A), allowing its escape from the promoter and elongation of the transcripts. Involved in cell cycle control and in RNA transcription by RNA polymerase II. Its expression and activity are constant throughout the cell cycle. Associates primarily with CDK7 and MAT1 to form the CAK complex. CAK can further associate with the core-TFIIH to form the TFIIH basal transcription factor. Belongs to the cyclin family. Cyclin C subfamily. Note: This description may include information from UniProtKB.
Molecular Function: RNA polymerase subunit kinase activity; DNA-dependent ATPase activity; protein binding; cyclin-dependent protein kinase regulator activity; protein kinase binding
Biological Process: transcription from RNA polymerase II promoter; ATP catabolic process; transcription initiation from RNA polymerase II promoter; viral reproduction; positive regulation of viral transcription; transcription from RNA polymerase I promoter; RNA elongation from RNA polymerase I promoter; termination of RNA polymerase I transcription; DNA repair; protein amino acid phosphorylation; mRNA capping; nucleotide-excision repair; transcription-coupled nucleotide-excision repair; RNA elongation from RNA polymerase II promoter; nucleotide-excision repair, DNA damage removal; gene expression; positive regulation of transcription from RNA polymerase II promoter; mitotic cell cycle; regulation of cyclin-dependent protein kinase activity; G2/M transition of mitotic cell cycle; transcription initiation from RNA polymerase I promoter; G1/S transition of mitotic cell cycle
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.