Different Heat Shock Proteins Bind α-Synuclein With Distinct Mechanisms and Synergistically Prevent Its Amyloid Aggregation

Chunyu Jia,Xiang Zhang,Jinge Gu,Xiaojuan Ma,Shengnan Zhang,Zhenying Liu,Dan Li

doi:10.3389/fnins.2019.01124

Abstract

α-Synuclein (α-Syn) forms pathological amyloid aggregates deposited in Lewy bodies and Lewy neurites in the brain of Parkinson’s disease (PD) patients. Heat shock proteins (Hsps) are the major components of the cellular chaperone network, which are responsible for preventing proteins from amyloid aggregation. Different Hsps were reported to interact with α-syn. However, the underlying mechanism of the interplay between α-syn and different Hsps remains unclear. Here, by combing NMR spectroscopy, electron microscope and other biochemical approaches, we systemically investigated the interaction between α-syn and three Hsps from different families including Hsp27, HDJ1, and Hsp104. We found that all three Hsps can weakly bind to α-syn and inhibit it from amyloid aggregation. Intriguingly, different Hsps recognize distinct regions of α-syn monomer, and act synergistically in chaperoning α-syn from fibril formation in sub-stoichiometry. Our results revealed the diverse binding mechanisms employed by different Hsps to tackle α-syn, and suggested that different Hsps form a network for cooperatively chaperoning α-syn from pathological aggregation.

Highlights

Maintenance of protein homeostasis is essential in living cells (Gidalevitz et al, 2011; Balchin et al, 2016), failure of which may lead to abnormal protein aggregation that closely associated with a variety of devastating human neurodegenerative disease including Alzheimer’s disease, Parkinson’s disease (PD), and amyotrophic lateral sclerosis (Chiti and Dobson, 2006; Eisenberg and Jucker, 2012; Cohen et al, 2015; Yerbury et al, 2016)
We first sought to investigate whether and how the ubiquitous small Heat shock proteins (Hsps) (sHsps) — Hsp27 (Figure 1A) modulates the pathological amyloid aggregation of α-syn. α-Syn monomer and Hsp27 multimer were purified from E. coli and characterized by gel filtration (Supplementary Figures S1, S2)
We further prepared the purified ACD of Hps27 (Figure 1A and Supplementary Figure S2), which was previously reported to be responsible for the chaperone activity of Hsp27 for its amyloid client – Tau (Freilich et al, 2018b)

Summary

Introduction

Maintenance of protein homeostasis is essential in living cells (Gidalevitz et al, 2011; Balchin et al, 2016), failure of which may lead to abnormal protein aggregation that closely associated with a variety of devastating human neurodegenerative disease including Alzheimer’s disease, Parkinson’s disease (PD), and amyotrophic lateral sclerosis (Chiti and Dobson, 2006; Eisenberg and Jucker, 2012; Cohen et al, 2015; Yerbury et al, 2016). The family members include Hsp100, Hsp, Hsp, Hsp, Hsp, and the small Hsps (sHsps), which are classified by their distinct molecular mass in. Hsps Chaperone α-Syn From Aggregation the unit of kilodalton (Saibil, 2013). They commonly exist with high abundancy throughout the three kingdoms of life. Different members of Hsp family feature distinct chaperone activities (e.g., disaggregase activity of Hsp100, holdase activity of Hsp and sHsps, and foldase activity of Hsp60), and form an elaborate network for maintaining the protein homeostasis (Itoh et al, 1995; Glover and Lindquist, 1998; Shorter and Lindquist, 2004; Hasegawa et al, 2017; Liu et al, 2017, 2018)

Methods

Results

Conclusion