Protein Misfolding and Aggregation

National Heart, Lung, And Blood Institute

Investigators

Linked publications & trials

Abstract

We have carried out detailed investigations of membrane interactions and amyloid formation of alpha-synuclein that have provided residue-specific information and molecular insights into the mechanism of aggregation. Due to the complexity of the amyloid problem, the tools with which we attack have included molecular biology, steady-state and time-resolved fluorescence spectroscopy, nuclear magnetic resonance spectroscopy, electron microscopy, neutron reflectometry, and mass spectrometry. Through our work, we are developing a chemical understanding in how specific biomolecular interactions and cellular environments modulate protein structure and aggregation propensity. We have made substantial contributions in the biophysical studies of alpha-synucleinlipid interactions and the biochemical analysis of alpha-synuclein in the lysosome, a cellular organelle for proteolysis. Broadly, we are exploring how alpha-synuclein structure responds to the complex nature of cellular milieu and testing the hypothesis that its conformational plasticity is modulating its function. Understanding how chemical environments influence alpha-synuclein conformation is crucial in defining cellular scenarios where amyloid formation occurs and how the aggregation process may lead to deleterious consequences such as membrane deformation and remodeling. In addition, we are interested in understanding the effect of post-translational modifications and processing on alpha-synuclein fibril formation and structure as it is highly relevant to the proteostasis network. Recently, we have gained structural insights of alpha-synuclein fibril structures by cryoelectron microscopy, which has motivated studies on fibril propagation at the residue-level. Biologically, this is pertinent as fibril templating and propagation are key processes in amyloid accumulation. We are testing several hypotheses involving electrostatic interactions such as the formation of salt bridges is rate-limiting for fibril growth. We are also interested in the interplay of amyloid structures as it now recognized that in vivo, heterologous propagation may be prevalent and could contribute to disease phenotypes.