Fig. 1.

Abi1 is a downstream substrate of Bcr-Abl tyrosine kinase. A. Ba/F3 and 32D cells were transduced with empty retroviral vector (control) or retroviral vector expressing p185^Bcr-Abl (p185^wt). Total lysates from 1×10⁶ cells were analyzed by Western blot (WB) using indicated antibodies. B. Tyrosine phosphorylation of Abi1 in Bcr-Abl-transformed hematopoietic cells. Ba/F3 cells and the Ba/F3 expressing either p185^wt or p185^K671R were treated with or without 1 μM imatinib mesylate, as indicated. The lysates from 2×10⁷ cells were immunoprecipitated (IP) with anti-Abi1 antibody, followed by Western blot analysis using anti-phosphotyrosine (α-pTyr) antibody (upper panel). The blots were then stripped and re-probed with anti-Abi1 antibody (lower panel). The relative molecular mass (M_r) is indicated and presented as kilodaltons (kd).