title: The axonally secreted serine proteinase inhibitor, neuroserpin, inhibits plasminogen activators and plasmin but not thrombin.
abstract: Neuroserpin is an axonally secreted serine proteinase inhibitor that is expressed in neurons during embryogenesis and in the adult nervous system. To identify target proteinases, we used a eucaryotic expression system based on the mouse myeloma cell line J558L and vectors including a promoter from an Ig-kappa-variable region, an Ig-kappa enhancer, and the exon encoding the Ig-kappa constant region (C kappa) and produced recombinant neuroserpin as a wild-type protein or as a fusion protein with C kappa. We investigated the capability of recombinant neuroserpin to form SDS-stable complexes with, and to reduce the amidolytic activity of, a variety of serine proteinases in vitro. Consistent with its primary structure at the reactive site, neuroserpin exhibited inhibitory activity against trypsin-like proteinases. Although neuroserpin bound and inactivated plasminogen activators and plasmin, no interaction was observed with thrombin. A reactive site mutant of neuroserpin neither formed complexes with nor inhibited the amidolytic activity of any of the tested proteinases. Kinetic analysis of the inhibitory activity revealed neuroserpin to be a slow binding inhibitor of plasminogen activators and plasmin. Thus, we postulate that neuroserpin could represent a regulatory element of extracellular proteolytic events in the nervous system mediated by plasminogen activators or plasmin.
authors.affiliation: Institute of Biochemistry, University of Zurich, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Osterwalder
authors.forename: P
authors.initials: P
authors.lastname: Cinelli
authors.forename: A
authors.initials: A
authors.lastname: Baici
authors.forename: A
authors.initials: A
authors.lastname: Pennella
authors.forename: S R
authors.initials: SR
authors.lastname: Krueger
authors.forename: S P
authors.initials: SP
authors.lastname: Schrimpf
authors.forename: M
authors.initials: M
authors.lastname: Meins
authors.forename: P
authors.initials: P
authors.lastname: Sonderegger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000378:metabolism*; D002642:Chick Embryo; D005341:Fibrinolysin / Q000037:antagonists & inhibitors*; D005822:Genetic Vectors; D006023:Glycoproteins / Q000378:metabolism*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000378:metabolism*; D010960:Plasminogen Activators / Q000037:antagonists & inhibitors*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D015842:Serine Proteinase Inhibitors / Q000378:metabolism*; D015843:Serpins / Q000378:metabolism*; D013917:Thrombin / Q000037:antagonists & inhibitors*; D010959:Tissue Plasminogen Activator / Q000037:antagonists & inhibitors; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000037:antagonists & inhibitors; D000097522:Neuroserpin
chemical_list: D005341:Fibrinolysin; D006023:Glycoproteins; D007145:Immunoglobulin kappa-Chains; D009479:Neuropeptides; D010960:Plasminogen Activators; D011994:Recombinant Proteins; D015842:Serine Proteinase Inhibitors; D015843:Serpins; D013917:Thrombin; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator; D000097522:Neuroserpin