Phosphotyrosine immunoblots and control staining of the same blots (after strip-washes) with anti-Abl or anti-actin antibodies.

(A) K562-sensitive and -resistant clones after a 2-hour incubation with graded concentrations of STI751. (B) K562-, KCL22-, AR230-, and LAMA84-resistant sublines incubated for 8 days in the presence (+) or absence (−) of 1 μmol/L STI571. The arrows indicate protein bands of approximately 110 and 55 to 58 kd, which become or remain hyperphosphorylated in K562-r and KCL22-r, respectively.