Identification of CDK8 and CDK19 substrates in human cells using cortistatin A and quantitative phosphoproteomics

ABSTRACT: Cortistatin A (CA) is a highly selective inhibitor of the Mediator kinases CDK8 and CDK19. Using CA, we report here the first large-scale identification of Mediator kinase substrates in human cells (HCT116). Among over 16,000 quantified sites, we identified 78 high-confidence Mediator kinase targets within 64 proteins, including DNA-binding transcription factors and proteins associated with chromatin, DNA repair, and RNA polymerase II. Although RNA-seq data correlated with Mediator kinase targets, CA effects on gene expression were limited and distinct from CDK8 or CDK19 knockdown. Quantitative proteome analyses, which tracked about 7,000 proteins across six time points (0-24h), revealed that CA selectively affected pathways implicated in inflammation, growth, and metabolic regulation; contrary to expectations, increased turnover of Mediator kinase targets was not generally observed. Collectively, these data support Mediator kinases as regulators of chromatin and RNA polymerase II activity and suggest roles beyond transcription, including metabolism and DNA repair.

OTHER RELATED OMICS DATASETS IN: PRJNA313158

INSTRUMENT(S): LTQ Orbitrap, LTQ Orbitrap Velos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell, Cell Culture

DISEASE(S): Colon Cancer

SUBMITTER: Zach Poss  

LAB HEAD: Dylan J Taatjes

PROVIDER: PXD003698 | Pride | 2018-10-24

REPOSITORIES: Pride