How can we visualize CSK activity in live cells? This research develops a genetically encoded biosensor based on fluorescence resonance energy transfer (FRET) to visualize C-terminal Src kinase (CSK) activity in live cells, shedding light on its regulatory mechanisms and subcellular localization. The biosensor, with an optimized substrate peptide, confirmed the crucial Arg107 site in the CSK SH2 domain and displayed sensitivity and specificity to CSK activity, showing minor responses to co-transfected Src and Fyn. FRET measurements showed that CSK had a relatively mild level of kinase activity in comparison to Src and Fyn in rat airway smooth muscle cells. The biosensor detected CSK activity at both non-lipid raft and lipid raft microregions, while showing a higher FRET level at non-lipid ones. This novel FRET biosensor monitors CSK activity and demonstrates its presence in both non-lipid and lipid raft membrane microregions, contributing to our understanding of CSK regulation.
Published in Sustainability, this research may seem out of place, but it possibly aligns with the journal’s broader interest in sustainable technologies and their applications. The development of a FRET biosensor could be considered a tool for sustainable biomedical research, providing insights into cellular processes and contributing to future therapies, thus resonating with the journal’s interdisciplinary approach.