Angular Approach Scanning Ion Conductance Microscopy.
Biophysical Journal 110(10):2252 (2016)
Scanning ion conductance microscopy (SICM) is a super-resolution live imaging technique that uses a glass nanopipette as an imaging probe to produce three-dimensional (3D) images of cell surface. SICM can be used to analyze cell morphology at nanoscale, follow membrane dynamics, precisely positi...
Remarkably low affinity of CD4/peptide-major histocompatibility complex class II protein interactions.
PNAS 113(20):5682 (2016)
The αβ T-cell coreceptor CD4 enhances immune responses more than 1 million-fold in some assays, and yet the affinity of CD4 for its ligand, peptide-major histocompatibility class II (pMHC II) on antigen-presenting cells, is so weak that it was previously unquantifiable. Here, we report that a so...
Ca2+ is a key factor in α-synuclein-induced neurotoxicity.
Development 143(10):e1.1 (2016)
Initiation of T cell signaling by CD45 segregation at 'close contacts'.
Nature Immunology 17(5):574 (2016)
It has been proposed that the local segregation of kinases and the tyrosine phosphatase CD45 underpins T cell antigen receptor (TCR) triggering, but how such segregation occurs and whether it can initiate signaling is unclear. Using structural and biophysical analysis, we show that the extracell...
Ca2+ is a key factor in α-synuclein-induced neurotoxicity.
Journal of Cell Science 129(9):1792 (2016)
Aggregation of α-synuclein leads to the formation of oligomeric intermediates that can interact with membranes to form pores. However, it is unknown how this leads to cell toxicity in Parkinson's disease. We investigated the species-specific effects of α-synuclein on Ca(2+) signalling in primary...
Spearhead Nanometric Field-Effect Transistor Sensors for Single-Cell Analysis.
ACS Nano 10(3):3214 (2016)
Nanometric field-effect-transistor (FET) sensors are made on the tip of spear-shaped dual carbon nanoelectrodes derived from carbon deposition inside double-barrel nanopipettes. The easy fabrication route allows deposition of semiconductors or conducting polymers to comprise the transistor chann...
Single-Molecule Imaging of Individual Amyloid Protein Aggregates in Human Biofluids.
ACS Chemical Neuroscience 7(3):399 (2016)
The misfolding and aggregation of proteins into amyloid fibrils characterizes many neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. We report here a method, termed SAVE (single aggregate visualization by enhancement) imaging, for the ultrasensitive detection of individua...
Kinetic model of the aggregation of alpha-synuclein provides insights into prion-like spreading.
PNAS 113(9):E1206 (2016)
The protein alpha-synuclein (αS) self-assembles into small oligomeric species and subsequently into amyloid fibrils that accumulate and proliferate during the development of Parkinson's disease. However, the quantitative characterization of the aggregation and spreading of αS remains challenging...
Alpha-Synuclein Oligomers Interact with Metal Ions to Induce Oxidative Stress and Neuronal Death in Parkinson's Disease.
Antioxidants and Redox Signaling 24(7):376 (2016)
Protein aggregation and oxidative stress are both key pathogenic processes in Parkinson's disease, although the mechanism by which misfolded proteins induce oxidative stress and neuronal death remains unknown. In this study, we describe how aggregation of alpha-synuclein (α-S) from its monomeric...
PSD95 nanoclusters are postsynaptic building blocks in hippocampus circuits.
Scientific reports 6:24626 (2016)
The molecular features of synapses in the hippocampus underpin current models of learning and cognition. Although synapse ultra-structural diversity has been described in the canonical hippocampal circuitry, our knowledge of sub-synaptic organisation of synaptic molecules remains largely unknown...
Quantitative analysis of co-oligomer formation by amyloid-beta peptide isoforms.
Scientific reports 6:28658 (2016)
Multiple isoforms of aggregation-prone proteins are present under physiological conditions and have the propensity to assemble into co-oligomers with different properties from self-oligomers, but this process has not been quantitatively studied to date. We have investigated the amyloid-β (Aβ) pe...
Referenced Single-Molecule Measurements Differentiate between GPCR Oligomerization States.
Biophysical Journal 109(9):1798 (2015)
The extent to which Rhodopsin family G-protein-coupled receptors (GPCRs) form invariant oligomers is contentious. Recent single-molecule fluorescence imaging studies mostly argue against the existence of constitutive receptor dimers and instead suggest that GPCRs only dimerize transiently, if at...
Fast flow microfluidics and single-molecule fluorescence for the rapid characterization of α-synuclein oligomers.
Analytical chemistry 87(17):8818 (2015)
α-Synuclein oligomers can be toxic to cells and may be responsible for cell death in Parkinson's disease. Their typically low abundance and highly heterogeneous nature, however, make such species challenging to study using traditional biochemical techniques. By combining fast-flow microfluidics ...
Lipid peroxidation is essential for α-synuclein-induced cell death.
Journal of Neurochemistry 133(4):582 (2015)
Parkinson's disease is the second most common neurodegenerative disease and its pathogenesis is closely associated with oxidative stress. Deposition of aggregated α-synuclein (α-Syn) occurs in familial and sporadic forms of Parkinson's disease. Here, we studied the effect of oligomeric α-Syn on ...
Structural characterization of toxic oligomers that are kinetically trapped during α-synuclein fibril formation.
PNAS 112(16):E1994 (2015)
We describe the isolation and detailed structural characterization of stable toxic oligomers of α-synuclein that have accumulated during the process of amyloid formation. Our approach has allowed us to identify distinct subgroups of oligomers and to probe their molecular architectures by using c...
SICM-Based Nanodelivery System for Local TRPV1 Stimulation
Biophysical Journal 108(2):332a (2015)
Single-molecule FRET reveals hidden complexity in a protein energy landscape.
Structure 23(1):190 (2015)
Here, using single-molecule FRET, we reveal previously hidden conformations of the ankyrin-repeat domain of AnkyrinR, a giant adaptor molecule that anchors integral membrane proteins to the spectrin-actin cytoskeleton through simultaneous binding of multiple partner proteins. We show that the an...
Single-molecule FRET studies on alpha-synuclein oligomerization of Parkinson's disease genetically related mutants.
Scientific reports 5:16696 (2015)
Oligomers of alpha-synuclein are toxic to cells and have been proposed to play a key role in the etiopathogenesis of Parkinson's disease. As certain missense mutations in the gene encoding for alpha-synuclein induce early-onset forms of the disease, it has been suggested that these variants migh...
A mechanistic model of tau amyloid aggregation based on direct observation of oligomers.
Nature Communications 6:7025 (2015)
Protein aggregation plays a key role in neurodegenerative disease, giving rise to small oligomers that may become cytotoxic to cells. The fundamental microscopic reactions taking place during aggregation, and their rate constants, have been difficult to determine due to lack of suitable methods ...
On-demand delivery of single DNA molecules using nanopipets.
ACS Nano 9(4):3587 (2015)
Understanding the behavioral properties of single molecules or larger scale populations interacting with single molecules is currently a hotly pursued topic in nanotechnology. This arises from the potential such techniques have in relation to applications such as targeted drug delivery, early st...