Figure 6.

G451E p55 fails to coimmunoprecipitate with p140. The p140-dependent coimmunoprecipitation of WT p55 or G451E p55 with immobilized anti-p140 rabbit antibodies was assayed as described in the “Subjects and Methods” section. Samples contained WT p55 alone (lane 1), p140 catalytic subunit and WT p55 (lane 2), G451E mutant p55 (lane 3), p140 and G451E mutant p55 (lane 4), or 0.2 μg each of p140 and p55 loaded directly as positive controls for the western blot (lane 5). The positions of p140 and p55 standards are indicated with arrows.