Document Detail


Protease nexins: cell-secreted proteins that mediate the binding, internalization, and degradation of regulatory serine proteases.
MedLine Citation:
PMID:  6317700     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The protease nexins (PN-I, Mr approximately 38,000; PN-II, Mr approximately 95,000; and PN-III, Mr approximately 31,000) are recently described cell-secreted proteins that selectively link to regulatory serine proteases in the extracellular environment and mediate their cellular binding, internalization, and degradation. In the present studies we compared the protease nexins with respect to protease specificity, heparin sensitivity, and general mode of action. By competitive binding assays using [125I]-thrombin, [125I]-nerve growth factor-gamma (125I-NGF-gamma), and [125I]-epidermal growth factor binding protein (125I-EGF-binding protein), we characterized the nexins in terms of protease specificity and determined that PN-I links to and mediates the cellular binding of thrombin or urokinase, whereas PN-II and PN-III preferentially link to and mediate the cellular binding of the EGF binding protein and NGF-gamma, respectively. In addition, whereas the ability of PN-I to link to thrombin is strongly modulated by heparin, PN-II and PN-III are essentially unaffected by heparin. The linkage of each of the nexins to their respective proteases requires the catalytic site serine of the protease, judged by the inability of diisopropylphospho (DIP) derivatives of the proteases tested to link to their respective nexins. Subsequent to linkage, the nexin:protease complexes are bound to cells, rapidly internalized, and ultimately degraded via a monensin-sensitive apparently lysosomal pathway, although each nexin:protease complex is degraded at its own characteristic rate. Importantly, the protease nexins provide the major pathway through which human fibroblasts interact with each of the serine proteases studied. Taken together, these data suggest that the nexins are a unique class of cell-secreted proteins that enable cells to monitor and selectively regulate specific serine proteases in their environment.
Authors:
D J Knauer; J A Thompson; D D Cunningham
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of cellular physiology     Volume:  117     ISSN:  0021-9541     ISO Abbreviation:  J. Cell. Physiol.     Publication Date:  1983 Dec 
Date Detail:
Created Date:  1984-02-14     Completed Date:  1984-02-14     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0050222     Medline TA:  J Cell Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  385-96     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Amyloid beta-Protein Precursor
Binding Sites
Carrier Proteins / metabolism,  physiology*
Cell Membrane / enzymology*
Cells, Cultured
Endocytosis
Endopeptidases / metabolism*
Fibroblasts
Heparin / pharmacology
Humans
Lysosomes / enzymology
Male
Monensin / pharmacology
Nerve Growth Factors / metabolism
Receptor, Epidermal Growth Factor
Receptors, Cell Surface / metabolism
Serine Endopeptidases
Thrombin / metabolism
Urokinase-Type Plasminogen Activator / metabolism
Grant Support
ID/Acronym/Agency:
CA 09054/CA/NCI NIH HHS; CA 12306/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Amyloid beta-Protein Precursor; 0/Carrier Proteins; 0/Nerve Growth Factors; 0/Receptors, Cell Surface; 0/protease nexins; 17090-79-8/Monensin; 9005-49-6/Heparin; EC 2.7.10.1/Receptor, Epidermal Growth Factor; EC 3.4.-/Endopeptidases; EC 3.4.21.-/Serine Endopeptidases; EC 3.4.21.5/Thrombin; EC 3.4.21.73/Urokinase-Type Plasminogen Activator

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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