Suppression of apolipoprotein C-II amyloid formation by the extracellular chaperone, clusterin

Abstract

The effect of the extracellular chaperone, clusterin, on amyloid fibril formation by lipid-free human apolipoprotein C-II (apoC-II) was investigated. Sub-stoichiometric levels of clusterin, derived from either plasma or semen, potently inhibit amyloid formation by apoC-II. Inhibition is dependent on apoC-II concentration, with more effective inhibition by clusterin observed at lower concentrations of apoC-II. The average sedimentation coefficient of apoC-II fibrils formed from apoC-II (0.3 mg·mL-1) is reduced by coincubation with clusterin (10 μg·mL-1). In contrast, addition of clusterin (0.1 mg·mL-1) to preformed apoC-II amyloid fibrils (0.3 mg·mL-1) does not affect the size distribution af..