Soluble β_c is retained on the surface of GMRα-expressing CHO cells. (A) CHO cells expressing GMRα and either full-length β_c (β_c ) or soluble β_c (sβ_c ) were ¹²⁵I–surface-labeled and immunoprecipitation was performed with anti-β_c MoAb (8E4). The immunoprecipitated proteins were then either incubated with (2) or without (1) deglycosylating enzymes and subsequently separated on 7.5% SDS-PAGE under reducing conditions and visualized by phosphorimager. (B) Soluble β_c was immunoprecipitated from the medium of CHO cells coexpressing GMRα and soluble β_c (sβ_c ) and the immunoprecipitated proteins were either subjected to enzymatic deglycosylation (2) or not (1) and subsequently separated on 7.5% SDS-PAGE. Western transfer was then performed and immunoblotting with anti-β_c antibody 1C1.