Document Detail


Regulation of single chain urokinase binding, internalization, and degradation by a plasminogen activator inhibitor 1-derived peptide.
MedLine Citation:
PMID:  9341144     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The internalization and degradation of cell-associated urokinase type plasminogen activator (uPA) through the alpha2-macroglobulin receptor/low density lipoprotein-related receptor (alpha2MR/LRP) represent important steps in the control of plasmin formation. Complexes between two chain urokinase (tcuPA) and plasminogen activator type 1 are degraded rapidly whereas single chain urokinase (scuPA) is not, suggesting that alpha2MR/LRP requires specific epitopes in the serpin for effective function. We report an alternative mechanism that may contribute to this process. The binding of scuPA to LM-TK- cells that lack the uPA receptor was stimulated by the hexapeptide EEIIMD, corresponding to amino acids 350-355 of plasminogen activator type 1, which contacts the sequence RHRGGS, corresponding to amino acids 179-184 in uPA. EEIIMD increased the Bmax of scuPA binding 4-fold with the half-maximal effect achieved at a peptide concentration of 50 microM. Stimulation was dependent on the charge on the COOH-terminal amino acid but not on the NH2 terminus of the peptide. EEIIMD also stimulated the internalization and degradation of scuPA. Both the binding and internalization of scuPA in the presence of EEIIMD were blocked by recombinant, 39-kDa alpha2MR/LRP-associated protein as well as by an anti-alpha2MR/LRP antibody. EEIIMD also stimulated the binding of scuPA to purified alpha2MR/LRP. EEIIMD had no effect on the binding of tcuPA or of complexes between scuPA and its receptor. These results suggest that EEIIMD regulates the binding of scuPA with alpha2MR/LRP. These findings also suggest a potential mechanism by which scuPA can be cleared which is independent of activation by plasmin or binding to uPA receptor.
Authors:
L Zhang; D K Strickland; D B Cines; A A Higazi
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  272     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1997 Oct 
Date Detail:
Created Date:  1997-11-28     Completed Date:  1997-11-28     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  27053-7     Citation Subset:  IM    
Affiliation:
Departments of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Animals
Binding Sites
Cell Line
Endocytosis
Epitopes / analysis
Fibrinolysin / metabolism
Kinetics
LDL-Receptor Related Protein 1
Macromolecular Substances
Oligopeptides / pharmacology
Peptide Fragments / metabolism,  pharmacology*
Plasminogen Activator Inhibitor 1 / chemistry*,  pharmacology*
Receptors, Cell Surface / metabolism*
Receptors, Immunologic / metabolism*
Receptors, Urokinase Plasminogen Activator
Recombinant Proteins / chemistry,  metabolism
Urokinase-Type Plasminogen Activator / chemistry*,  metabolism*
Grant Support
ID/Acronym/Agency:
HL40387/HL/NHLBI NIH HHS; HL49517/HL/NHLBI NIH HHS; HL50790/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Epitopes; 0/LDL-Receptor Related Protein 1; 0/Macromolecular Substances; 0/Oligopeptides; 0/Peptide Fragments; 0/Plasminogen Activator Inhibitor 1; 0/Receptors, Cell Surface; 0/Receptors, Immunologic; 0/Receptors, Urokinase Plasminogen Activator; 0/Recombinant Proteins; EC 3.4.21.7/Fibrinolysin; 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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