Membrane Receptor Mapping: The Membrane Topography of FcεRI Signaling

摘要: Ligand binding to membrane receptors initiates cascades of biochemical events leading physiological responses. Hundreds proteins and lipids are implicated in signaling networks programs genomics proteomics continuously adding new components the “parts lists”. Here, we generate high resolution maps using cytoplasmic face-up sheets that can be labeled with inununogold probes (3–10 nm) imaged transmission electron microscope. Our model system is mast cell focus on mapping topography affinity IgE receptor, FceRI, its associated tyrosine kinases, Lyn Syk, propagate signals from these kinases. Crosslinked their partners segregate during multiple, dynamic domains, including a transient FceRI-Lyn domain at least two other distinct one characterized by presence Syk multiple proteins, but not (primary domains), LAT PLCγl receptor (secondary domains). PI 3-kinase associates both primary secondary domains may help recruit specific through local remodeling inositol phospholipids. The lipid raft markers, GM1 Thy-1, fail localize native either each or domains. We introduce molecules same sheet computational tools capture analyze topographical relationships. In future, expect will integrated chemical kinetic analyses, fractionation data range real-time fluorescence measurements, into mathematical models power predict mechanisms regulate efficiency, specificity, amplitude duration pathways.