Molecular Mechanisms of Protein C Deficiency Caused by P275S Mutation

Objective To study the molecular mechanisms of protein C(PC) deficiency caused by PC P275S mutation.Methods Wild-type and P275S mutant PC cDNA expression plasmids were constructed and transfected into HEK 293T cells and COS 7 cells,respectively.ELISA was used to detect the PC antigens.The expression of PC mRNA was investigated by real time RT-PCR.Immunofluorescent assay was utilized to analyze the distribution of PC in the endoplasmic reticulum and Golgi complex.Results Compared to the wide type,P275S mutant PC antigens in the supernatant of culture medium and cell lysates were 22.6% and 78.9% separately.Real time RT-PCR analysis of the total mRNA from transfected cells showed no reduction of the P275S mutant PC mRNA expression.Immunofluorescent assay revealed that wild type PC protein was distributed largely in both endoplasmic reticulum and Golgi complex,while the PC P275S mutant protein was mainly located in the endoplasmic reticulum.Conclusion Impaired secretion and degradation intracellularly of the mutant PC might be the molecular mechanisms of PC deficiency caused by P275S mutation.