TY - JOUR
T1 - Induction, inhibition, and incorporation
T2 - Different roles for anionic and zwitterionic lysolipids in the fibrillation of the functional amyloid FapC
AU - Rasmussen, Helena Østergaard
AU - Otzen, Daniel E
AU - Pedersen, Jan Skov
N1 - Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.
PY - 2022/2
Y1 - 2022/2
N2 - Amyloid proteins are widespread in nature both as pathological species involved in several diseases and as functional entities that can provide protection and storage for the organism. Lipids have been found in amyloid deposits from various amyloid diseases and have been shown to strongly affect the formation and structure of both pathological and functional amyloid proteins. Here, we investigate how fibrillation of the functional amyloid FapC from Pseudomonas is affected by two lysolipids, the zwitterionic lipid 1-myristoyl-2-hydroxy-sn-glycero-3- phosphocholine (LPC) and the anionic lipid 1-myristoyl-2-hydroxy-sn-glycero-3- phospho-(1'-rac-glycerol) (LPG). Small-angle X-ray scattering (SAXS), circular dichroism (CD), dynamic light scattering (DLS), and thioflavin T fluorescence measurements were performed simultaneously on the same sample to ensure reproducibility and allow a multimethod integrated analysis. We found that LPG strongly induces fibrillation around its critical micelle concentration (cmc) by promoting formation of large structures, which mature via accumulation of intermediate fibril structures with a large cross section. At concentrations above its cmc, LPG strongly inhibits fibrillation by locking FapC in a core-shell complex. In contrast, LPC induces fibrillation at concentrations above its cmc, not via strong interactions with FapC but by being incorporated during fibrillation and likely stabilizing the fibrillation nucleus to reduce the lag phase. Finally, we show LPG is not incorporated into the fibril during assembly, but rather can coat the final fibril. We conclude that lipids affect both the mechanism and outcome of fibrillation of functional amyloid, highlighting a role for lipid concentration and composition in the onset and mechanism of fibrillation in vivo.
AB - Amyloid proteins are widespread in nature both as pathological species involved in several diseases and as functional entities that can provide protection and storage for the organism. Lipids have been found in amyloid deposits from various amyloid diseases and have been shown to strongly affect the formation and structure of both pathological and functional amyloid proteins. Here, we investigate how fibrillation of the functional amyloid FapC from Pseudomonas is affected by two lysolipids, the zwitterionic lipid 1-myristoyl-2-hydroxy-sn-glycero-3- phosphocholine (LPC) and the anionic lipid 1-myristoyl-2-hydroxy-sn-glycero-3- phospho-(1'-rac-glycerol) (LPG). Small-angle X-ray scattering (SAXS), circular dichroism (CD), dynamic light scattering (DLS), and thioflavin T fluorescence measurements were performed simultaneously on the same sample to ensure reproducibility and allow a multimethod integrated analysis. We found that LPG strongly induces fibrillation around its critical micelle concentration (cmc) by promoting formation of large structures, which mature via accumulation of intermediate fibril structures with a large cross section. At concentrations above its cmc, LPG strongly inhibits fibrillation by locking FapC in a core-shell complex. In contrast, LPC induces fibrillation at concentrations above its cmc, not via strong interactions with FapC but by being incorporated during fibrillation and likely stabilizing the fibrillation nucleus to reduce the lag phase. Finally, we show LPG is not incorporated into the fibril during assembly, but rather can coat the final fibril. We conclude that lipids affect both the mechanism and outcome of fibrillation of functional amyloid, highlighting a role for lipid concentration and composition in the onset and mechanism of fibrillation in vivo.
U2 - 10.1016/j.jbc.2022.101569
DO - 10.1016/j.jbc.2022.101569
M3 - Journal article
C2 - 35007533
SN - 0021-9258
VL - 298
JO - The Journal of Biological Chemistry
JF - The Journal of Biological Chemistry
IS - 2
M1 - 101569
ER -