The axonally secreted serine proteinase inhibitor, neuroserpin, inhibits plasminogen activators and plasmin but not thrombin

J Biol Chem. 1998 Jan 23;273(4):2312-21. doi: 10.1074/jbc.273.4.2312.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Axons / metabolism*
  • Chick Embryo
  • Fibrinolysin / antagonists & inhibitors*
  • Genetic Vectors
  • Glycoproteins / metabolism*
  • Immunoglobulin kappa-Chains / genetics
  • Kinetics
  • Mice
  • Molecular Sequence Data
  • Neuropeptides / metabolism*
  • Plasminogen Activators / antagonists & inhibitors*
  • Protein Conformation
  • Recombinant Proteins / metabolism
  • Sequence Alignment
  • Serine Proteinase Inhibitors / metabolism*
  • Serpins / metabolism*
  • Thrombin / antagonists & inhibitors*
  • Tissue Plasminogen Activator / antagonists & inhibitors
  • Tumor Cells, Cultured
  • Urokinase-Type Plasminogen Activator / antagonists & inhibitors

Substances

  • Glycoproteins
  • Immunoglobulin kappa-Chains
  • Neuropeptides
  • Recombinant Proteins
  • Serine Proteinase Inhibitors
  • Serpins
  • neuroserpin
  • Plasminogen Activators
  • Thrombin
  • Tissue Plasminogen Activator
  • Fibrinolysin
  • Urokinase-Type Plasminogen Activator