Jean-Baptiste Sibarita

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The cell division axis determines the future positions of daughter cells and is therefore critical for cell fate. The positioning of the division axis has been mostly studied in systems such as embryos or yeasts, in which cell shape is well defined. In these cases, cell shape anisotropy and cell polarity affect spindle orientation. It remains unclear(More)
Control of the establishment of cell polarity is an essential function in tissue morphogenesis and renewal that depends on spatial cues provided by the extracellular environment. The molecular role of cell-cell or cell-extracellular matrix (ECM) contacts on the establishment of cell polarity has been well characterized. It has been hypothesized that the(More)
The E-Cadherin-catenin complex plays a critical role in epithelial cell-cell adhesion, polarization, and morphogenesis. Here, we have analyzed the mechanism of Drosophila E-Cadherin (DE-Cad) localization. Loss of function of the Drosophila exocyst components sec5, sec6, and sec15 in epithelial cells results in DE-Cad accumulation in an enlarged Rab11(More)
Specialized cell types exploit endosomal trafficking to deliver protein cargoes to cell type-specific lysosome-related organelles (LROs), but how endosomes are specified for this function is not known. In this study, we show that the clathrin adaptor AP-1 and the kinesin motor KIF13A together create peripheral recycling endosomal subdomains in melanocytes(More)
We present a nonparametric regression method for denoising 3-D image sequences acquired via fluorescence microscopy. The proposed method exploits the redundancy of the 3-D+time information to improve the signal-to-noise ratio of images corrupted by Poisson-Gaussian noise. A variance stabilization transform is first applied to the image-data to remove the(More)
Invadopodia are actin-based membrane protrusions formed at contact sites between invasive tumor cells and the extracellular matrix with matrix proteolytic activity. Actin regulatory proteins participate in invadopodia formation, whereas matrix degradation requires metalloproteinases (MMPs) targeted to invadopodia. In this study, we show that the(More)
We present a non-parametric regression method for denoising flu-orescence video-microscopy volume sequences. The designed method aims at using the 3D+t information in order to restore acquired data contaminated by Poisson and Gaussian noise. We propose to use a variance stabilization transform to deal with the combination of Poisson and Gaussian noise.(More)
The spatiotemporal organization of neurotransmitter receptors in postsynaptic membranes is a fundamental determinant of synaptic transmission and information processing by the brain. Using four independent super-resolution light imaging methods and EM of genetically tagged and endogenous receptors, we show that, in rat hippocampal neurons, AMPARs are often(More)
To understand how nuclear machineries are targeted to accurate locations during nuclear assembly, we investigated the pathway of the ribosomal RNA (rRNA) processing machinery towards ribosomal genes (nucleolar organizer regions [NORs]) at exit of mitosis. To follow in living cells two permanently transfected green fluorescence protein-tagged nucleolar(More)