Structure of the archaeal chemotaxis protein CheY in a domain-swapped dimeric conformation

Archaea are motile by the rotation of the archaellum. The archaellum switches between clockwise and counterclockwise rotation, and movement along a chemical gradient is possible by modulation of the switching frequency. This modulation involves the response regulator CheY and the archaellum adaptor protein CheF. In this study, two new crystal forms and protein structures of CheY are reported. In both crystal forms, CheY is arranged in a domain-swapped conformation. CheF, the protein bridging the chemotaxis signal transduction system and the motility apparatus, was recombinantly expressed, purified and subjected to X-ray data collection

Different soluble aggregates of Aβ42 can give rise to cellular toxicity through different mechanisms.

Protein aggregation is a complex process resulting in the formation of heterogeneous mixtures of aggregate populations that are closely linked to neurodegenerative conditions, such as Alzheimer's disease. Here, we find that soluble aggregates formed at different stages of the aggregation process of amyloid beta (Aβ42) induce the disruption of lipid bilayers and an inflammatory response to different extents. Further, by using gradient ultracentrifugation assay, we show that the smaller aggregates are those most potent at inducing membrane permeability and most effectively inhibited by antibodies binding to the C-terminal region of Aβ42. By contrast, we find that the larger soluble aggregates are those most effective at causing an inflammatory response in microglia cells and more effectively inhibited by antibodies targeting the N-terminal region of Aβ42. These findings suggest that different toxic mechanisms driven by different soluble aggregated species of Aβ42 may contribute to the onset and progression of Alzheimer's disease.This study is supported by the Marie-Curie Individual Fellowship programme (S.D.), EPSRC Studentship (D.C.W.), Boehringer Ingelheim Fonds (P.F.), Studienstiftung des deutschen Volkes (P.F.), Senior Research Fellowship from the Alzheimer's Society, Grant Number 317, AS-SF-16-003, UK (F.A.A), Swiss National Fondation for Science and Darwin College grant number P2ELP2_162116 and P300P2_171219 (F.S.R.), Borysiewicz Biomedical Fellowship from the University of Cambridge(P.S), the UK Biotechnology and Biochemical Sciences Research Council (C.M.D.); the Wellcome Trust (C.M.D) the Cambridge Centre for Misfolding Diseases (P.F., F.A.A., P.S., C.M.D., and M.V.) and the European Research Council Grant Number 669237 (D.K.) and the Royal Society (D.K.)

Inhibiting the Ca2+ Influx Induced by Human CSF.

One potential therapeutic strategy for Alzheimer's disease (AD) is to use antibodies that bind to small soluble protein aggregates to reduce their toxic effects. However, these therapies are rarely tested in human CSF before clinical trials because of the lack of sensitive methods that enable the measurement of aggregate-induced toxicity at low concentrations. We have developed highly sensitive single vesicle and single-cell-based assays that detect the Ca2+ influx caused by the CSF of individuals affected with AD and healthy controls, and we have found comparable effects for both types of samples. We also show that an extracellular chaperone clusterin; a nanobody specific to the amyloid-β peptide (Aβ); and bapineuzumab, a humanized monoclonal antibody raised against Aβ, could all reduce the Ca2+ influx caused by synthetic Aβ oligomers but are less effective in CSF. These assays could be used to characterize potential therapeutic agents in CSF before clinical trials

Supplementary material from The human CTF4-orthologue AND-1 interacts with DNA polymerase α/primase via its unique C-terminal HMG box

Supplementary Table 1 and Figures S1-S

Inhibiting the Ca2+ Influx Induced by Human CSF

One potential therapeutic strategy for Alzheimer’s disease (AD) is to use antibodies that bind to small soluble protein aggregates to reduce their toxic effects. However, these therapies are rarely tested in human CSF before clinical trials because of the lack of sensitive methods that enable the measurement of aggregate-induced toxicity at low concentrations. We have developed highly sensitive single vesicle and single-cell-based assays that detect the Ca2+ influx caused by the CSF of individuals affected with AD and healthy controls, and we have found comparable effects for both types of samples. We also show that an extracellular chaperone clusterin; a nanobody specific to the amyloid-β peptide (Aβ); and bapineuzumab, a humanized monoclonal antibody raised against Aβ, could all reduce the Ca2+ influx caused by synthetic Aβ oligomers but are less effective in CSF. These assays could be used to characterize potential therapeutic agents in CSF before clinical trials

Nanoscopic Characterisation of Individual Endogenous Protein Aggregates in Human Neuronal Cells.

The aberrant misfolding and subsequent conversion of monomeric protein into amyloid aggregates characterises many neurodegenerative disorders, including Parkinson's and Alzheimer's diseases. These aggregates are highly heterogeneous in structure, generally of low abundance and typically smaller than the diffraction limit of light (≈250 nm). To overcome the challenges these characteristics pose to the study of endogenous aggregates formed in cells, we have developed a method to characterise them at the nanometre scale without the need for a conjugated fluorophore. Using a combination of DNA PAINT and an amyloid-specific aptamer, we demonstrate that this technique is able to detect and super-resolve a range of aggregated species, including those formed by α-synuclein and amyloid-β. Additionally, this method enables endogenous protein aggregates within cells to be characterised. We found that neuronal cells derived from patients with Parkinson's disease contain a larger number of protein aggregates than those from healthy controls.M.H.H. was supported by a Junior Research Fellowship at Christ’s College, University of Cambridge, and the Herchel Smith Foundation. Y.Z. was supported by Cambridge Trust and Chinese Scholarship Council. PF was supported by Boehringer Ingelheim Fonds, and the German National Merit Foundation. S.D. is funded by a Marie-Curie Individual Fellowship. C.M.D. is supported by the UK Biotechnology and Biochemical Sciences Research Council and the Wellcome Trust. This work was also supported by the Cambridge Centre for Misfolding Diseases (P.F., and C.M.D.), the Royal Society (D.K.), the European Research Council with an ERC Advanced Grant (669237) (D.R.W and D.K.), and the Allen Distinguished Investigator Program, through The Paul G. Allen Frontiers Group (M.H.H.). M.G.S. and L.C. were supported by the Cambridge Biomedical Research Centre at Addenbrooke’s hospital, Cambridge and the Allen Foundation