Soluble forms of GMRα and βc spontaneously associate when coexpressed and bind GM-CSF. (A) Conditioned medium from CHO cells coexpressing soluble GMRα and soluble βc was immunoprecipitated using either anti-βc (4F3), anti-GMRα (8G6), or a control antibody (9F5); and the proteins were separated on 10% SDS-PAGE, Western transferred, and immunoblotted with anti-βc antibody 1C1. (B) Conditioned medium from CHO cells either coexpressing soluble GMRα and soluble βc (sGMRα/sβc ) or a mixture of conditioned medium from CHO cells expressing the soluble proteins separately (sGMRα + βc ) were incubated with GM-CSF and immunoprecipitation was performed with anti–GM-CSF antibody. Proteins were separated on 10% SDS-PAGE, Western transferred, and then immunoblotted with anti-βc antibody 1C1.
