Phospholipids enhance nucleation but not elongation of apolipoprotein C-II amyloid fibrils

Abstract

Amyloid fibrils and their oligomeric intermediates accumulate in several age-related diseases where their presence is considered to play an active role in disease progression. A common characteristic of amyloid fibril formation is an initial lag phase indicative of a nucleation-elongation mechanism for fibril assembly. We have investigated fibril formation by human apolipoprotein (apo) C-II. ApoC-II readily forms amyloid fibrils in a lipid-dependent manner via an initial nucleation step followed by fibril elongation, breaking, and joining. We used fluorescence techniques and stopped-flow analysis to identify the individual kinetic steps involved in the activation of apoC-II fibril formation ..