Ligand binding to cell surface receptors initiates a cascade of signaling events regulated by
dynamic phosphorylation events on a multitude of pathway proteins. Quantitative features,
including intensity, timing, and duration of phosphorylation of particular residues, may play a
role in determining cellular response, but experimental data required for analysis of these
features have not previously been available. To understand the dynamic operation of
signaling cascades, we have developed a method enabling the simultaneous quantification …