Figure 4.

Identification of SRK oligomeric complexes in stigma extract. (A) Proteins were extracted from stigmas expressing the S₃ haplotype in a Triton X-100-containing buffer and either treated (+) or not (−) with the cross-linking reagent glutaraldehyde. Proteins then were separated by SDS/PAGE and immunoblotted with mAb 85–36-71. SRK₃-containing complexes of 161 and 233 kDa are indicated by arrows. Monomeric SRK₃ and eSRK₃ are indicated with an asterisk and an arrowhead, respectively. (B) Velocity sedimentation on sucrose gradients. Proteins were extracted in buffer containing octyl-glucoside, and stigma extracts were either supplemented with SDS at the concentration of 0.5% (mass/vol) (+SDS) or not (−SDS). The presence of SRK₃ (SRK), eSRK₃ (eSRK), and SLG₃ (SLG) in the different fractions was examined by immunoblotting with mAb 85–36-71 and anti-SLG₃ antibodies. The distribution of molecular mass markers (66, 150, and 200 kDa) is indicated at the bottom of each panel.