protein S; vitamin K-dependent protein S (PROS1, PROS)

Function

• anticoagulant plasma protein
• cofactor to activated protein C in the degradation of coagulation factor Va & factor VIIIa
• helps to prevent coagulation
• stimulates fibrinolysis
• vitamin K-dependent binding protein
• cofactor for protein C
• binds C4b-binding protein; 50% is protein bound
• only free form of protein S has biological activity

Structure

• contains 4 EGF-like domains
  • the iron & 2-oxoglutarate dependent 3-hydroxylation of Asp & Asn is (R) stereospecific within EGF domains
• contains 1 Gla (gamma-carboxy-glutamate) domain
• contains 2 laminin G-like domains

Compartment

secreted, plasma

Expression

• presumablu expressed in liver & secreted into plasma
• plasma activity may be reduced as a result of acute thrombosis
• anticoagulation may lower activity of protein S in plasma

Pathology

• defects in PROS1 are the cause of protein S deficiency
  • individuals with heterozygous protein S deficiency often develop thromboembolic disease before age 30

More general terms

• coagulation factor
• endogenous anticoagulant

More specific terms

• protein-S alpha
• protein-S beta

Additional terms

• coagulation cascade
• protein S activity in plasma (protein S assay)
• protein S deficiency

Component of

• factor ix/factor vii/factor x/protein c/protein s/prothrombin
• prothrombin complex concentrate (Autoplex-T, Kcentra)

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=5627
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:5627
• OMIM: https://mirror.omim.org/entry/176880
• OMIM: https://mirror.omim.org/entry/612336
• UniProt: http://www.uniprot.org/uniprot/P07225.html