The Ca²⁺- and sugar-binding sites in the CRD interacts with FV and FVIII. COS-1 cells were cotransfected with the wild-type or indicated LMAN1 mutants, along with either FV (A) or FVIII (A-B). Cells were incubated with or without DSP before lysis. Cell lysates were immunoprecipitated with preimmune serum (pre) as a negative control, anti-Flag (Flag) for LMAN1, and anti-FV (F5) or -FVIII (F8) for the indicated coagulation factor.