Chemical biology tools for protein labelling: insights into cell-cell communication 

Multicellular organisms require carefully orchestrated communication between and within cell types and tissues, and many unicellular organisms also sense their context and envir-onment, sometimes coordinating their responses. This review highlights contributions from chemical biology in discovering and probing mechanisms of cell-cell communica-tion. We focus on chemical tools for labelling proteins in a cellular context and how these can be applied to decipher the target receptor of a signalling molecule, label a receptor of interest in situ to understand its biology, provide a read-out of protein activity or inter-actions in downstream signalling pathways, or discover protein-protein interactions across cell-cell interfaces.