FIGURE 2.

ErbB4, but not ErbB1 to −3, is stimulated by NRG4 in colonocytes. YAMC-B4 cells were exposed to HRG-1β (100 ng/ml), NRG4 (100 ng/ml), or EGF (10 ng/ml) for 10 min. A, phosphorylation of EGFR, ErbB2, ErbB3, and ErbB4 was determined by Western blot analysis using phospho-specific antibodies. The dashed line indicates excision of a superfluous lane from the blot. B, ErbB4 was immunoprecipitated (IP), and immunocomplexes were subjected to Western blot analysis for EGFR, ErbB2, and ErbB3 to detect receptor co-association/dimerization. Blots are representative of results from at least three independent experiments.