FIG. 4.

Synthetic ligands can activate other members of the ErbB family, and the activated receptors retain their kinase specificity. (A) Total cell lysates from cells stimulated with AP1510 (nanomolar) or EGF (50 ng/ml) were resolved and blotted with anti-pTyr antibodies. The positions of p75.B1.F2.HA, p75.B2.F2.HA, and Shc are indicated. (B) The top two-thirds of the blot in panel A was stripped and reprobed with anti-phospho-473 Akt antibody (upper panel), and the blot was restripped and blotted with anti-Akt antibody (lower panel). (C) The lower third of the blot in panel A was stripped and reprobed with anti-Erk2. (D) c-Cbl was immunoprecipitated (IP) from 750 μg of lysate and immunoblotted with anti-pTyr antibodies (upper panel), and the blot was subsequently stripped and reprobed with anti-Cbl antibodies (lower panel). The position of the coimmunoprecipitated p75.B1.F2.HA is indicated.