Huttlin, E.L. et al. Cell 162, 425–440 (2015).

Proteins carry out their functions by interacting with other proteins in the cell. Affinity purification–mass spectrometry (AP-MS) has proven to be a valuable technique for detecting such interactions. As part of an effort to profile the entire collection of human open reading frames, Huttlin et al. performed a large-scale systematic AP-MS analysis of 2,594 human protein 'baits', detecting 23,744 interactions between 7,668 proteins in HEK293T cells. The resulting interactome network, which the authors term BioPlex, can be explored via a graphical viewer. They showed that the BioPlex network had nearly perfect overlap with protein complexes annotated in the CORUM mammalian protein database but also detected thousands of new interactions. BioPlex can be used to predict subcellular localization; to characterize the function of 'orphan' proteins, which do not belong to a known network; and to validate interaction subnetworks.