GM-CSF but not the GM-CSF analog E21R induces the assembly of the ternary GM-CSF receptor complex in solution.
The presence and molecular weight of individual proteins and protein complexes were determined using size-exclusion chromatography as described in “Materials and methods.” (A) Linear regression of log10 (MW × 10−3) versus elution times using external (○) and internal (●) standards for calibration of the column. (B-I) Individual proteins sGMRα (B), sβc (C), GM-CSF (D), and E21R (G) were applied separately. Mixtures of sGMRα (6 μM) and GM-CSF (12 μM) (E); sβc (3 μM), sGMRα (6 μM), and GM-CSF (12 μM) (F); sGMRα (6 μM) and E21R (12 μM) (H); sβc (3 μM), sGMRα (6 μM), and E21R (12 μM) (I) were incubated for 1 hour before being applied to the column. The number above each peak represents elution time. Peaks containing binary (BC) or ternary (TC) complexes are indicated.
