Cyclin-dependent kinase 8 and Cyclin-dependent kinase 19 (CDK8 and CDK19)

Cyclin-dependent kinase 8 and Cyclin-dependent kinase 19 are closely related serine/threonine protein kinases classified within the transcriptional CDKs subfamily. They function as integral components of the four-subunit CDK8 (or CDK19) module within the Mediator complex, which regulates transcription by RNA polymerase II. Both kinases require binding to cyclin C for activity and can reversibly associate with the Mediator complex, modulating transcriptional activation or repression by phosphorylating RNA polymerase II and diverse transcription factors. CDK8/19 play crucial roles in enhancer function, signaling-induced transcription, and, uniquely, in regulating the phosphorylation of proteins involved in mitochondrial fission. As regulatory nodes in gene expression, they have been implicated as oncogenes (notably in colorectal cancer), but can also act as tumor suppressors in specific signaling contexts. Pharmacological inhibition of CDK8/19 is under exploration for cancer therapy, but clinical safety and efficacy remain under investigation due to complex tissue-specific roles and possible impacts on global transcriptional regulation[1][3][4][6][7][8].

Other names

CDK8CDK19Cell division protein kinase 8Cell division protein kinase 19CDK11 (for CDK19, less commonly used)CDC2L6 (for CDK19, less commonly used)

Inhibition of CDK8/19 kinase activity (reducing phosphorylation of transcriptional targets) Disruption of Mediator complex kinase function Modulation of Wnt/β-catenin signaling (antagonizes oncogenic transcription)