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cyclin H (MO15-associated protein, CCNH)

Function: - cyclin component of CDK-activating kinase - regulates CDK7, the catalytic subunit of the CDK-activating kinase (CAK) enzymatic complex - CAK activates the cyclin-associated kinases CDC2/CDK1, CDK2, CDK4 & CDK6 by threonine phosphorylation - CAK complexed to the core-TFIIH basal transcription factor activates RNA polymerase 2 by serine phosphorylation of the repetitive C-terminus domain (CTD) of its large subunit (POLR2A), allowing its escape from the promoter & elongation of the transcripts - involved in cell cycle control & in RNA transcription by RNA polymerase 2 - expression & activity are constant throughout the cell cycle - associates primarily with CDK7 & MAT1 to form the CAK complex - CAK can further associate with the core-TFIIH to form the TFIIH basal transcription factor Structure: belongs to the cyclin family. cyclin C subfamily Compartment: nucleus

General

cyclin phosphoprotein

Properties

SIZE: entity length = 323 aa MW = 38 kD COMPARTMENT: cell nucleus MOTIF: Ser phosphorylation site {S5} Ser phosphorylation site {S304} glutamate-rich region {310-313} MOTIF: glutamate residue (SEVERAL) Thr phosphorylation site {T315}

Database Correlations

OMIM 601953 UniProt P51946 Pfam PF00134 Entrez Gene 902 Kegg hsa:902

References

  1. Solomon MJ. The function(s) of CAK, the p34cdc2-activating kinase. Trends Biochem Sci. 1994 Nov;19(11):496-500. PMID: 7855894
  2. UniProt :accession P51946

Component-of

CDK7/cyclin H complex, CDK-activating kinase (CAK) or p34cdc2 activating kinase