CTD kinase subunit alpha

UniProtKB accession:  Q03957

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UniProtKB description:  Catalytic subunit of the CTDK-I complex, which hyperphosphorylates the C-terminal heptapeptide repeat domain (CTD) of the largest RNA polymerase II subunit. CTDK-I phosphorylates 'Ser-5' if the CTD substrate is not phosphorylated at 'Ser-5', but will phosphorylate 'Ser-2' of a CTD substrate if 'Ser-5' is already phosphorylated. CTDK-I is also more reactive toward substrates that are prephosphorylated at 'Ser-2' or 'Ser-5' compared with an unphosphorylated CTD substrate, therefore efficiently creating doubly phosphorylated CTD repeats. Involved in RNA polymerase II transcriptional elongation, and through PTI1, pre-mRNA 3'-end processing. Participates in both positive and negative regulation of CTD phosphorylation. Required for DNA damage induced transcription, including the expression of the RNR genes, and reprogramming of gene expression upon amino acid starvation. Required for SET2 mediated H3K36 methylation. Also regulates H3K4 methylation. Controls the maintenance of suppressive chromatin in the coding regions of genes by both promoting H3K36 methylation, which leads to histone deacetylation, and catalyzing phosphorylation of the CTD required to localize H3K4 chromatin modification specifically to the 5' ends of genes, thereby creating a boundary for H3K4 methylation that prevents a mark associated with transcriptional initiation from spreading into the bodies of genes. Involved in RNA polymerase I transcription. Involved in telomere maintenance. Acts together with SNF1 to induce GSY2 transcription in response to glucose limitation. Involved in the adaptation to alternative carbon sources, including galactose, glycerol and ethanol, but not raffinose. Required for the integrity of the rDNA locus. Functions in translation elongation by enhancing decoding fidelity. Needed for translational accuracy by phosphorylating RPS2.