Signaling pathways transmit information through protein interaction networks that are dynamically regulated by complex extracellular cues. We developed LUMIER (for luminescence-based mammalian interactome mapping), an automated high-throughput technology, to map protein-protein interaction networks systematically in mammalian cells and applied it to the transforming growth factorâÎ² (TGFÎ²) pathway. Analysis using self-organizing maps and k -means clustering identified links of the TGFÎ² pathway to the p21-activated kinase (PAK) network, to the polarity complex, and to Occludin, a structural component of tight junctions. We show that Occludin regulates TGFÎ² type I receptor localization for efficient TGFÎ²-dependent dissolution of tight junctions during epithelial-to-mesenchymal transitions.

High-Throughput Mapping of a Dynamic Signaling Network in Mammalian Cells