A quantitative approach to signal transduction.

The high affinity receptor for IgE (FcepsilonRI), is one of a family of immunoreceptors whose antigen-induced clustering leads to a variety of cellular responses. The signaling pathways are enormously complex but by focusing on only the most initial steps, it is now possible to sketch plausible molecular models that relate the interaction of multivalent antigens with the receptor-bound IgE to the earliest cellular events. In this paper, we describe how we have combined quantitative experimentation and mathematical modeling to probe this system further. We also discuss some of the formidable challenges that remain before we can claim reasonably complete understanding of even these early events.