Ephrins are transmembrane proteins that bind ephrin receptors on adjacent cells, leading to propagation of biochemical signals within both cells. Jørgensen et al. devised a way to use differential isotopic labeling to distinguish cells engineered to express either the receptor or the ligand and to monitor bidirectional signaling events by mass spectrometry of the labeled peptides when the cells were mixed together. Signaling networks were constructed, and the information processing by the two interacting cell types was modeled. Changes in signaling within cells expressing just the ligand (ephrin) caused changes in the signal processing during the adjacent cell’s response to binding of the ephrin receptor.
C. Jørgensen, A. Sherman, G. I. Chen, A. Pasculescu, A. Poliakov, M. Hsiung, B. Larsen, D. G. Wilkinson, R. Linding, T. Pawson, Cell-specific information processing in segregating populations of Eph receptor ephrin–expressing cells. Science 326, 1502–1509 (2009). [Abstract] [Full Text]