5hvy

Structural highlights

Function

[CDK8_HUMAN] Component of the Mediator complex, a coactivator involved in regulated gene transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors. Phosphorylates the CTD (C-terminal domain) of the large subunit of RNA polymerase II (RNAp II), which may inhibit the formation of a transcription initiation complex. Phosphorylates CCNH leading to down-regulation of the TFIIH complex and transcriptional repression. Recruited through interaction with MAML1 to hyperphosphorylate the intracellular domain of NOTCH, leading to its degradation.^{[1] [2]} [CCNC_HUMAN] Component of the Mediator complex, a coactivator involved in regulated gene transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors. Binds to and activates cyclin-dependent kinase CDK8 that phosphorylates the CTD (C-terminal domain) of the large subunit of RNA polymerase II (RNAp II), which may inhibit the formation of a transcription initiation complex.^{[3] [4]}

References

1. ↑ Akoulitchev S, Chuikov S, Reinberg D. TFIIH is negatively regulated by cdk8-containing mediator complexes. Nature. 2000 Sep 7;407(6800):102-6. PMID:10993082 doi:10.1038/35024111
2. ↑ Fryer CJ, White JB, Jones KA. Mastermind recruits CycC:CDK8 to phosphorylate the Notch ICD and coordinate activation with turnover. Mol Cell. 2004 Nov 19;16(4):509-20. PMID:15546612 doi:S1097276504006409
3. ↑ Rickert P, Seghezzi W, Shanahan F, Cho H, Lees E. Cyclin C/CDK8 is a novel CTD kinase associated with RNA polymerase II. Oncogene. 1996 Jun 20;12(12):2631-40. PMID:8700522
4. ↑ Baek HJ, Kang YK, Roeder RG. Human Mediator enhances basal transcription by facilitating recruitment of transcription factor IIB during preinitiation complex assembly. J Biol Chem. 2006 Jun 2;281(22):15172-81. Epub 2006 Apr 4. PMID:16595664 doi:M601983200
5. ↑ Bergeron P, Koehler MF, Blackwood EM, Bowman K, Clark K, Firestein R, Kiefer JR, Maskos K, McCleland ML, Orren L, Ramaswamy S, Salphati L, Schmidt S, Schneider EV, Wu J, Beresini M. Design and Development of a Series of Potent and Selective Type II Inhibitors of CDK8. ACS Med Chem Lett. 2016 Apr 5;7(6):595-600. doi: 10.1021/acsmedchemlett.6b00044. , eCollection 2016 Jun 9. PMID:27326333 doi:http://dx.doi.org/10.1021/acsmedchemlett.6b00044