Effect of iFGFR activation on baseline phosphorylation of EphB2. EphB2+iFGFR cells were incubated with AP20187 to activate iFGFR, and samples were collected at intervals for immunoprecipitation and Western blot analysis to detect tyrosine phosphorylation of iFGFR (a, top) and of EphB2 (a, bottom). The time course of phosphorylation is shown in b. Phosphorylation of iFGFR rapidly increases within minutes, and baseline (ephrin independent) phosphorylation of EphB2 progressively increases over an 8-h period. Error bars indicate range (n = 3). Tyr, tyrosine.