title: The binding of protein S and the protein S-C4BP complex to neutrophils is apoptosis dependent.
abstract: Vitamin K-dependent protein S and complement regulator C4b-binding protein (C4BP) form a high-affinity complex in plasma. We have previously shown that both free protein S and the C4BP-protein S complex can bind to apoptotic Jurkat cells. It has been demonstrated in the past that protein S and C4BP can bind to neutrophils. We now show that it is only the apoptotic neutrophil population that binds these proteins. In addition, we also show that binding is mediated through the Gla domain on protein S, which binds negatively charged phospholipids, since a monoclonal antibody directed against this domain blocks the binding. Thus, we conclude that binding of protein S and the C4BP-protein S complex to neutrophils is not cell specific, but rather apoptosis dependent.
authors.affiliation: Division of Clinical Chemistry, Department of Laboratory Medicine, Lund University, Sweden.
authors.forename: Joanna H
authors.initials: JH
authors.lastname: Webb
authors.forename: Anna M
authors.initials: AM
authors.lastname: Blom
authors.forename: Björn
authors.initials: B
authors.lastname: Dahlbäck
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D001665:Binding Sites / Q000276:immunology; D061945:Caspase Inhibitors; D015935:Complement C4b / Q000378:metabolism; D003169:Complement Inactivator Proteins / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D006023:Glycoproteins; D006801:Humans; D019169:Jurkat Cells / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology / Q000378:metabolism*; D009842:Oligopeptides; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D017293:Protein S / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D061945:Caspase Inhibitors; D003169:Complement Inactivator Proteins; D015853:Cysteine Proteinase Inhibitors; D006023:Glycoproteins; D009842:Oligopeptides; D017293:Protein S; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; D015935:Complement C4b