title: Protease nexin-II (amyloid beta-protein precursor): a platelet alpha-granule protein.
abstract: Protease nexin-II (PN-II) [amyloid beta-protein precursor (APP)] and the amyloid beta-protein are major constituents of neuritic plaques and cerebrovascular deposits in individuals with Alzheimer's disease and Down syndrome. Both the brain and the circulation have been implicated as sources of these molecules, although they have not been detected in blood. Human platelets have now been found to contain relatively large amounts of PN-II/APP. Platelet PN-II/APP was localized in platelet alpha-granules and was secreted upon platelet activation. Because PN-II/APP is a potent protease inhibitor and possesses growth factor activity, these results implicate PN-II/APP in wound repair. In certain disease states, alterations in platelet release and processing and clearance of PN-II/APP and its derived fragments could lead to pathological accumulation of these proteins.
authors.affiliation: Department of Microbiology and Molecular Genetics, University of California, Irvine 92717.
authors.forename: W E
authors.initials: WE
authors.lastname: Van Nostrand
authors.forename: A H
authors.initials: AH
authors.lastname: Schmaier
authors.forename: J S
authors.initials: JS
authors.lastname: Farrow
authors.forename: D D
authors.initials: DD
authors.lastname: Cunningham
mesh_terms: D000682:Amyloid / Q000097:blood* / Q000302:isolation & purification; D016229:Amyloid beta-Peptides / Q000097:blood* / Q000302:isolation & purification; D016564:Amyloid beta-Protein Precursor; D000911:Antibodies, Monoclonal; D001792:Blood Platelets / Q000737:chemistry*; D002458:Cell Fractionation; D003594:Cytoplasmic Granules / Q000737:chemistry*; D004815:Epidermal Growth Factor / Q000097:blood; D006801:Humans; D015151:Immunoblotting; D015849:Plasminogen Inactivators / Q000097:blood; D015539:Platelet Activation; D011498:Protein Precursors / Q000097:blood* / Q000302:isolation & purification
chemical_list: D000682:Amyloid; D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D000911:Antibodies, Monoclonal; D015849:Plasminogen Inactivators; D011498:Protein Precursors; D004815:Epidermal Growth Factor