Publications by authors named "Jervis Vermal Thevathasan"

BAX and BAK are key apoptosis regulators that mediate the decisive step of mitochondrial outer membrane permeabilization. However, the mechanism by which they assemble the apoptotic pore remains obscure. Here, we report that BAX and BAK present distinct oligomerization properties, with BAK organizing into smaller structures with faster kinetics than BAX.

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Interferometric single-molecule localization microscopy (iPALM, 4Pi-SMS) uses multiphase interferometry to localize single fluorophores and achieves nanometer isotropic resolution in 3D. The current data analysis workflow, however, fails to reach the theoretical resolution limit due to the suboptimal localization algorithm. Here, we develop a method to fit an experimentally derived point spread function (PSF) model to the interference 4Pi-PSF.

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Here we describe the use of an organotypic hippocampal slice model for studying α-synuclein aggregation and inter-neuronal spreading initiated by microinjection of pre-formed α-synuclein fibrils (PFFs). PFF injection at dentate gyrus (DG) templates the formation of endogenous α-synuclein aggregates in axons and cell bodies of this region that spread to CA3 and CA1 regions. Aggregates are insoluble and phosphorylated at serine-129, recapitulating Lewy pathology features found in Parkinson's disease and other synucleinopathies.

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Quantitative fluorescence and superresolution microscopy are often limited by insufficient data quality or artifacts. In this context, it is essential to have biologically relevant control samples to benchmark and optimize the quality of microscopes, labels and imaging conditions. Here, we exploit the stereotypic arrangement of proteins in the nuclear pore complex as in situ reference structures to characterize the performance of a variety of microscopy modalities.

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Lesions and mutations of the DISC1 (Disrupted-in-schizophrenia-1) gene have been linked to major depression, schizophrenia, bipolar disorder and autism, but the influence of DISC1 on synaptic transmission remains poorly understood. Using two independent genetic approaches-RNAi and a DISC1 KO mouse-we examined the impact of DISC1 on the synaptic vesicle (SV) cycle by population imaging of the synaptic tracer vGpH in hippocampal neurons. DISC1 loss-of-function resulted in a marked decrease in SV exocytic rates during neuronal stimulation and was associated with reduced Ca(2+) transients at nerve terminals.

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STIMs (STIM1 and STIM2 in mammals) are transmembrane proteins that reside in the endoplasmic reticulum (ER) and regulate store-operated Ca(2+) entry (SOCE). The function of STIMs in the brain is only beginning to be explored, and the relevance of SOCE in nerve cells is being debated. Here we identify STIM2 as a central organizer of excitatory synapses.

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Article Synopsis
  • Self-amplification of phosphoinositide 3-kinase (PI3K) signaling is crucial for controlling asymmetric membrane extension and the migration of NIH3T3 fibroblasts.
  • Inducing PI3K activation leads to a uniform production of 3'-phosphoinositides (3-PIs), which then amplifies and creates asymmetric signaling that drives cell movement.
  • The feedback loop involving PI3K and the small GTPase HRas is necessary for effective cell migration, as silencing HRas disrupts this amplification and shortens cell protrusions, preventing migration.
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