Factor VII deficiency: Unveiling the cellular and molecular mechanisms underlying three model alterations of the enzyme catalytic domain

Publication date: March 2018 Source:Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, Volume 1864, Issue 3 Author(s): Maria Eugenia Chollet, Elisabeth Andersen, Ellen Skarpen, Christiane F. Myklebust, Christian Koehler, Jens Preben Morth, Ampaiwan Chuansumrit, Mirko Pinotti, Francesco Bernardi, Bernd Thiede, Per Morten Sandset, Grethe Skretting Activated factor (F) VII is a vitamin K-dependent glycoprotein that initiates blood coagulation upon interaction with tissue factor. FVII deficiency is the most common of the rare congenital bleeding disorders. While the mutational pattern has been extensively characterized, the pathogenic molecular mechanisms of mutations, particularly at the intracellular level, have been poorly defined. Here, we aimed at elucidating the mechanisms underlying altered FVII biosynthesis in the presence of three mutation types in the catalytic domain: a missense change, a microdeletion and a frameshift/elongation, associated with severe or moderate to severe phenotypes. Using CHO-K1 cells transiently transfected with expression vectors containing the wild-type FVII cDNA (FVIIwt) or harboring the p.I289del, p.G420V or p.A354V-p.P464Hfs mutations, we found that the secretion of the FVII mutants was severely decreased compared to FVIIwt. The synthesis rate of the mutants was slower than the FVIIwt and delayed, and no degradation of the FVII mutants by proteasomes, lysosomes or cysteine proteases was observed. Confocal immunofl...
Source: Biochimica et Biophysica Acta (BBA) Molecular Basis of Disease - Category: Molecular Biology Source Type: research