Kinases are essential regulators of cellular signaling and play key roles in diverse biological processes including apoptosis, cell cycle progression, and cellular growth. Dysregulation of kinase activity is linked to numerous pathologies such as cancer, infectious disease, and autoimmune disorders. While many kinases have been well characterised, a substantial subset of the human kinome remains understudied. These “dark” kinases represent a critical gap in our understanding of human biology.
Several dark kinases contain ubiquitin-binding or ubiquitin-associated (UBA) domains, suggesting potential crosstalk between kinase signaling and the ubiquitin system. However, the functional relevance of these domains remains largely unexplored. We set to investigate four such dark kinases: the AMPK-related kinases BRSK1, BRSK2, and NUAK2, and the atypical kinase RIOK3.
Interaction studies, such as surface plasmon resonance (SPR) and TurboID-based proximity labeling, are used to probe ubiquitin chain-binding specificity, and identify interacting partners. Binding to specific ubiquitin chain types may indicate potential cellular functions. We also employ kinase activity and substrate profiling assays to explore the functional roles and potential substrate(s) of these dark kinases.
Our studies aim to uncover novel molecular features and functional roles of these dark kinases, revealing previously uncharacterised links between ubiquitin binding and kinase activity.