Fibrillar Amyloid β-Protein Binds Protease Nexin-2/Amyloid β-Protein Precursor: Stimulation of Its Inhibition of Coagulation Factor XIa
| Autor: | Auspaker Kr, Van Nostrand We, Wagner Mr, Keane Dm, Melchor Jp |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Amyloid
Amyloid beta medicine.medical_treatment Receptors Cell Surface Biochemistry Factor XIa Amyloid beta-Protein Precursor mental disorders medicine Humans Protein precursor DNA Primers Amyloid beta-Peptides Protease Base Sequence biology Chemistry P3 peptide medicine.disease Trypsin Cell biology Protease Nexins biology.protein Cerebral amyloid angiopathy Carrier Proteins Binding domain medicine.drug |
| Zdroj: | Biochemistry. 39:7420-7427 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi0002840 |
| Popis: | Cerebrovascular deposition of fibrillar 39-42 amino acid amyloid beta-protein (Abeta), a condition known as cerebral amyloid angiopathy (CAA), is a key pathological feature of Alzheimer's disease and related disorders including hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D). Severe cases of CAA, particularly in HCHWA-D, lead to recurrent and often fatal hemorrhagic strokes. Although the reasons for this pathological consequence remain unclear, alterations in proteolytic hemostasis mechanisms have been implicated. For example, the Abeta parent molecule protease nexin-2/amyloid beta-protein precursor (PN-2/AbetaPP), which is elevated in HCHWA-D cerebral vessels with Abeta deposits, is a potent inhibitor of coagulation factor XIa (FXIa). Here we show that fibrillar HCHWA-D Abeta binds PN-2/AbetaPP, but not its isolated Kunitz-type proteinase inhibitor (KPI) domain, in a saturable, dose-dependent manner with a K(d) of approximately 28 nM. Neither PN-2/AbetaPP nor its KPI domain bound to nonfibrillar HCHWA-D Abeta. The fibrillar Abeta binding domain on PN-2/AbetaPP was localized to residues 18-119. PN-2/AbetaPP that bound to fibrillar HCHWA-D Abeta immobilized either in plastic wells or on the surface of cultured cerebrovascular smooth muscle cells was active in inhibiting FXIa. Quantitative kinetic measurements revealed that fibrillar HCHWA-D Abeta caused a >5-fold enhancement of FXIa inhibition by PN-2/AbetaPP. Similar stimulatory effects on FXIa inhibition by PN-2/AbetaPP were also observed with fibrillar wild-type Abeta. However, fibrillar Abeta had no effect on the inhibition of trypsin by PN-2/AbetaPP. These findings suggest that fibrillar Abeta deposits in cerebral vessels can effectively localize and enhance the anticoagulant functions of PN-2/AbetaPP, thereby contributing to a microenvironment conducive to hemorrhaging. |
| Databáze: | OpenAIRE |
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