title: Analysis of Gas6 in human platelets and plasma.
abstract: OBJECTIVE
  Gas6 is a member of the vitamin K-dependent protein family. Gas6-deficient mice were found to be resistant to thrombosis because of defective platelet function. Mouse Gas6 was demonstrated to be present in platelets and found to be involved in platelet aggregation. The aim of this study was to investigate the presence of Gas6 in human platelets and plasma and determine its role in platelet function.
  
  
  RESULTS
  The presence of Gas6 in human platelets and plasma was analyzed using sensitive immunologic methods. Mass spectrometry and ELISA were used to identify and quantify Gas6 in plasma. Gas6 was demonstrated to be present in human plasma, at a concentration determined to be 13 to 23 ng/mL (0.16 to 0.28 nM). Furthermore, plasma Gas6 levels were found to be lower in patients administered with warfarin. However, Gas6 was undetectable in human platelets.
  
  
  CONCLUSIONS
  This is the first report to identify and quantify Gas6 in human plasma. However, Gas6 protein was not detected in human platelets, suggesting that any potential platelet-specific function could be because of Gas6 from the circulation. These findings open up new directions regarding the role of Gas6 in normal and pathophysiological situations such as inflammation, autoimmune disease, thrombosis and arteriosclerosis.
authors.affiliation: Department of Laboratory Medicine, Division of Clinical Chemistry, Lund University, Wallenberg Laboratory, University Hospital Malmö, Sweden.
authors.forename: Istvan
authors.initials: I
authors.lastname: Balogh
authors.forename: Sassan
authors.initials: S
authors.lastname: Hafizi
authors.forename: Jonas
authors.initials: J
authors.lastname: Stenhoff
authors.forename: Karin
authors.initials: K
authors.lastname: Hansson
authors.forename: Björn
authors.initials: B
authors.lastname: Dahlbäck
mesh_terms: D000925:Anticoagulants / Q000627:therapeutic use; D001792:Blood Platelets / Q000737:chemistry / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis / Q000097:blood* / Q000276:immunology; D008297:Male; D013058:Mass Spectrometry; D012015:Reference Standards; D012680:Sensitivity and Specificity; D014859:Warfarin / Q000627:therapeutic use; D000099255:Growth Arrest-Specific Protein 6
chemical_list: D000925:Anticoagulants; D036341:Intercellular Signaling Peptides and Proteins; D014859:Warfarin; D000099255:Growth Arrest-Specific Protein 6