Analog-sensitive cell line identifies cellular substrates of CDK9.

Analog-sensitive cell line identifies cellular substrates of CDK9. Oncotarget. 2019 Dec 10;10(65):6934-6943 Authors: Decker TM, Forné I, Straub T, Elsaman H, Ma G, Shah N, Imhof A, Eick D Abstract Transcriptional cyclin-dependent kinases regulate all phases of transcription. Cyclin-dependent kinase 9 (CDK9) has been implicated in the regulation of promoter-proximal pausing of RNA polymerase II and more recently in transcription termination. Study of the substrates of CDK9 has mostly been limited to in vitro approaches that lack a quantitative assessment of CDK9 activity. Here we analyzed the cellular phosphoproteome upon inhibition of CDK9 by combining analog-sensitive kinase technology with quantitative phosphoproteomics in Raji B-cells. Our analysis revealed the activity of CDK9 on 1102 phosphosites quantitatively, and we identified 120 potential cellular substrates. Furthermore, a substantial number of CDK9 substrates were described as splicing factors, highlighting the role of CDK9 in transcription-coupled splicing events. Based on comparison to in vitro data, our findings suggest that cellular context fundamentally impacts the activity of CDK9 and specific selection of its substrates. PMID: 31857848 [PubMed]
Source: Oncotarget - Category: Cancer & Oncology Tags: Oncotarget Source Type: research