Human PROS1 (Vitamin K-dependent protein S) ELISA Kit

Hereditary protein S deficiency is one of the natural anticoagulant deficiency causing thrombophilia. Protein S deficiency is caused by a mutation in the PROS1 gene on 3q11.2 and is typically inherited in an autosomal dominant manner. We herein describe a Korean man with protein S deficiency from a novel nonsense mutation of PROS1. The patient was a 47-year-old man with deep-vein thrombosis. No relevant family history was documented. Coagulation test results included a significantly decreased protein S activity at 30%. Molecular genetic analysis targeting PROS1 on suspicion of hereditary protein S deficiency revealed that he was heterozygous for a novel transversion mutation, c.903C>G, in the exon 9 of PROS1. The mutation was predicted to result in premature termination at the codon 301 in the laminin G-type domain (p.Tyr301*) of the protein (nonsense mutation). According to a review of the literature and database, the mutation described herein is the first substitution mutation affecting the codon 301 of PROS1. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

Anticoagulant protein S (PS) in platelets (PSplt) resembles plasma PS and is released on platelet activation, but its role in thrombosis has not been elucidated. Here we report that inactivation of PSplt expression using the Platelet factor 4 (Pf4)-Cre transgene (Pros1(lox/lox)Pf4-Cre(+)) in mice promotes thrombus propensity in the vena cava, where shear rates are low, but not in the carotid artery, where shear rates are high. At a low shear rate, PSplt functions as a cofactor for both activated protein C and tissue factor pathway inhibitor, thereby limiting factor X activation and thrombin generation within the growing thrombus and ensuring that highly activated platelets and fibrin remain localized at the injury site. In the presence of high thrombin concentrations, clots from Pros1(lox/lox)Pf4-Cre2(-) mice contract, but not clots from Pros1(lox/lox)Pf4-Cre(+) mice, because of highly dense fibrin networks. Thus, PSplt controls platelet activation as well as coagulation in thrombi in large veins, but not in large arteries.