CDK6 activity in a recurring convergent kinase network motif. Issue 4 (8th March 2023)

• Record Type: Journal Article
• Authors: Gangemi, Christina G; Sabapathy, Rahkesh T.; Janovjak, Harald
• Is Part Of: FASEB journal. Volume 37:Issue 4(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-08
• Subjects: convergence -- inhibitor -- kinase -- protein engineering -- signaling network; Biology -- Periodicals; Biology, Experimental -- Periodicals; 570
• DOI: 10.1096/fj.202201344R
• Languages: English
• ISSNs: 0892-6638

Abstract

Abstract: In humans, more than 500 kinases phosphorylate ~15% of all proteins in an emerging phosphorylation network. Convergent local interaction motifs, in which ≥two kinases phosphorylate the same substrate, underlie feedback loops and signal amplification events but have not been systematically analyzed. Here, we first report a network‐wide computational analysis of convergent kinase‐substrate relationships (cKSRs). In experimentally validated phosphorylation sites, we find that cKSRs are common and involve >80% of all human kinases and >24% of all substrates. We show that cKSRs occur over a wide range of stoichiometries, in many instances harnessing co‐expressed kinases from family subgroups. We then experimentally demonstrate for the prototypical convergent CDK4/6 kinase pair how multiple inputs phosphorylate the tumor suppressor retinoblastoma protein (RB) and thereby hamper in situ analysis of the individual kinases. We hypothesize that overexpression of one kinase combined with a CDK4/6 inhibitor can dissect convergence. In breast cancer cells expressing high levels of CDK4, we confirm this hypothesis and develop a high‐throughput compatible assay that quantifies genetically modified CDK6 variants and inhibitors. Collectively, our work reveals the occurrence, topology, and experimental dissection of convergent interactions toward a deeper understanding of kinase networks and functions. Abstract : Gangemi et al. explored the complex relationships of human kinases and their substrates (top) using a combination of bioinformatics (bottom left) and cell‐based assays (bottom right). They focused on understanding convergent local network motifs in which more than one kinase phosphorylates the same substrate or the same site on a substrate. They found that these motifs are common and can be decoded in the case of the CDK4/6 pair using a combination of kinase inhibition and overexpression.