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

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 factor-{szligbeta} (TGF{szligbeta}) pathway. Analysis using self-organizing maps and k-means clustering identified links of the TGF{szligbeta} 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 TGF{szligbeta} type I receptor localization for efficient TGF{szligbeta}-dependent dissolution of tight junctions during epithelial-to-mesenchymal transitions.