Characterization of the GGCX truncation mutations identified from patients/animals with bleeding disorders by cell-based activity assay. (A) Carboxylation activity of wild-type GGCX and the I553* and E630* mutants measured by GGCX-deficient cell-based assay with 5 µg/mL vitamin K. (B) Carboxylation of the reporter protein by wild-type GGCX and the I553* and E630* mutants in GGCX-deficient HEK293 reporter cells in response to increasing concentrations of vitamin K. (C) Proposed membrane topology of GGCX according to Tie et al.18 GGCX truncation mutations and the corresponding amino acid residues are indicated (∇). N-linked glycosylation sites are indicated by Y. (D) Carboxylation activity of wild-type GGCX and the W315X, Q374X, R687X, and R704X mutants measured by GGCX-deficient cell-based assay with 5 µg/mL vitamin K. (E) Carboxylation of the reporter protein by wild-type GGCX and the R687X and R704X mutants in GGCX-deficient HEK293 reporter cells in response to increasing concentrations of vitamin K.
