Reversible protein phosphorylation forms vast signalling networks that rapidly respond to intra- and extra-cellular cues to orchestrate molecular responses, linking the cell’s genome with its environment. The misregulation of such signals cause or exacerbate the onset of complex diseases including cancer and ageing, and their rectification is therefore a major area of biomedical research. This is however complicated by the fact that major signaling nodes are functionally pleiotropic, being involved in several biological processes. Indeed, different cellular stimuli often signal through shared network branches. Designing effective therapies against dysregulated signalling therefore requires a more complete picture of the signalling landscapes downstream of cell surface receptors and the extent of network overlap.

Using EasyPhos1 – a new scalable, single-run phosphoproteomics platform – we quantified the response of signalling networks of diverse cell lines to a large panel of ligands, targeting pro-survival (e.g. EGF, IGF, VEGF, PDGF) and pro-inflammatory pathways (e.g. TNFα, TRAIL, IL1β, IL-6). We quantified over 20,000 phosphorylation sites, from which comparisons of ligand induced cellular signaling networks have been visualized, revealing highly specific network branches as well as large tracts of shared signalling components.

These systems-wide data provide an extensive view of ligand-induced signalling networks in different cell lines, greatly extending the current knowledge of the signalling occurring downstream of major cell surface receptors.