Expression of wild-type and mutant fibrinogen chains in COS-1 cells.

Intracellular and secreted fibrinogen from COS-1 cells transfected with wild-type Aα and γ-chains together with wild-type and/or L353R or G400D Bβ, chains have been analyzed. Metabolic labeling, immunoprecipitation, and SDS-PAGE were carried out as described in “Materials and Methods.” (A) Immunoprecipitable proteins in cell lysates separated on 4% SDS-PAGE under nonreducing conditions. The arrowhead indicates the 340-kd fibrinogen complex. (B) Immunoprecipitable proteins in the culture media separated on 4% SDS-PAGE under nonreducing conditions. The arrowhead indicates the 340-kd fibrinogen complex. (C) Immunoprecipitable proteins in the culture media separated on 10% SDS-PAGE under reducing conditions. The positions of Aα, Bβ, and γ chains are indicated. The position of molecular weight markers (MW) in kd is denoted at the right-hand side of the figure.