Coimmunoprecipitation demonstrating interactions between βC-R with VEGF-R2 and EPO-R. CD34⁺ EPCs were treated with EPO (50 mU/mL) or VEGF (100 ng/mL) or mock-treated for 3 hours before lysing the cells and immunoprecipitating with an αVEGF-R2 rabbit IgG (10 μg/mL), an αβC-R mouse IgG2b (2 μg/mL), or a mouse IgG2b (20 μg/mL). The immunoprecipitated products were separated by SDS-PAGE, transferred to nitrocellulose, and probed with an αVEGF-R2 antibody, followed by membrane stripping and reprobing with EPO-R antibody.