Figure 7.

ΔMEKK1 and JNK compete for binding to JNKK1. (A) Cell lysates containing GST–JNKK1 or a mixture of GST–JNKK1 lysate with ΔMEKK1-containing lysate were mixed with increasing amounts of HA–JNK1-containing lysates. The mixtures were precipitated with GSH–Sepharose, resolved by SDS-PAGE, and immunoblotted with anti-HA (top) and anti-MEKK1 (bottom). (B) Lysates containing GST–JNKK1 were mixed with increasing amounts of ΔMEKK1-containing lysates in the absence or presence of HA–JNK1-containing lysates. The mixtures were precipitated with GSH–Sepharose and analyzed as described above.