Publications by Paul Guichard | EPFL Graph Search

A helical inner scaffold provides a structural basis for centriole cohesion

Henning Paul-Julius Stahlberg, Virginie Hamel, Paul Guichard, Davide Gambarotto

The ninefold radial arrangement of microtubule triplets (MTTs) is the hallmark of the centriole, a conserved organelle crucial for the formation of centrosomes and cilia. Although strong cohesion between MTTs is critical to resist forces applied by ciliary ...

2020

Architecture of the centriole cartwheel‐containing region revealed by cryo‐electron tomography

Henning Paul-Julius Stahlberg, Virginie Hamel, Paul Guichard

Centrioles are evolutionarily conserved barrels of microtubule triplets that form the core of the centrosome and the base of the cilium. While the crucial role of the proximal region in centriole biogenesis has been well documented, its native architecture ...

2020

Novel features of centriole polarity and cartwheel stacking revealed by cryo-tomography

Pierre Gönczy, Davide Demurtas, Alexandra Bezler, Sergey Nazarov, Paul Guichard, Veronika Nemcíková Villímová, Georgios Hatzopoulos

Centrioles are polarized microtubule-based organelles that seed the formation of cilia, and which assemble from a cartwheel containing stacked ring oligomers ofSAS-6 proteins. A cryo-tomography map of centrioles from the termite flagellateTrichonymphaspp. ...

2020

Homogeneous multifocal excitation for high-throughput super-resolution imaging

Pierre Gönczy, Virginie Hamel, Suliana Manley, Paul Guichard, Dora Mahecic, Kyle Michael Douglass, Denis Fortun, Niccolo Banterle, Khalid Ashraf Mohie Ibrahim, Davide Gambarotto

Super-resolution microscopies have become an established tool in biological research. However, imaging throughput remains a main bottleneck in acquiring large datasets required for quantitative biology. Here we describe multifocal flat illumination for fie ...

2020

Imaging cellular ultrastructures using expansion microscopy (U-ExM)

Michaël Unser, Virginie Hamel, Paul Guichard, Denis Fortun, Davide Gambarotto

Determining the structure and composition of macromolecular assemblies is a major challenge in biology. Here we describe ultrastructure expansion microscopy (U-ExM), an extension of expansion microscopy that allows the visualization of preserved ultrastruc ...

2019

Flagellar microtubule doublet assembly in vitro reveals a regulatory role of tubulin C-terminal tails

Davide Demurtas, Virginie Hamel, Paul Guichard

Microtubule doublets (MTDs), consisting of an incomplete B-microtubule at the surface of a complete A-microtubule, provide a structural scaffold mediating intraflagellar transport and ciliary beating. Despite the fundamental role of MTDs, the molecular mec ...

American Association for the Advancement of Science2019

Reconstruction From Multiple Particles for 3D Isotropic Resolution in Fluorescence Microscopy

Michaël Unser, Pierre Gönczy, Virginie Hamel, Paul Guichard, Denis Fortun, Niccolo Banterle

Institute of Electrical and Electronics Engineers2018

Super-resolution microscopy to decipher multi-molecular assemblies

Suliana Manley, Paul Guichard, Kyle Michael Douglass, Christian Sieben

2018

The Rise of the Cartwheel: Seeding the Centriole Organelle

Pierre Gönczy, Virginie Hamel, Paul Guichard

2018

Cell-free reconstitution reveals centriole cartwheel assembly mechanisms

Henning Paul-Julius Stahlberg, Pierre Gönczy, Mircea Ioan Iacovache, Virginie Hamel, Isabelle Fluckiger, Paul Guichard, Veronika Nemcíková Villímová, Niccolo Banterle

How cellular organelles assemble is a fundamental question in biology. The centriole organelle organizes around a nine-foldsymmetrical cartwheel structure typically 100 nm high comprising a stack of rings that each accommodates nine homodimers of SAS-6 pro ...

Springer Nature2017

Identification of Chlamydomonas Central Core Centriolar Proteins Reveals a Role for Human WDR90 in Ciliogenesis

Pierre Gönczy, Coralie Busso, Virginie Hamel, Florence Armand, Isabelle Fluckiger, Romain Hamelin, Paul Guichard

Centrioles are evolutionarily conserved macromolecular structures that are fundamental to form cilia, flagella, and centrosomes. Centrioles are 9-fold symmetrical microtubule-based cylindrical barrels comprising three regions that can be clearly distinguis ...

2017

Isotropic Resolution in Fluorescence Imaging by Single Particle Reconstruction

Michaël Unser, Paul Guichard, Ning Chu, Denis Fortun

Low axial resolution is a major limitation of fluorescence imaging modalities. We propose a methodology to achieve high isotropic resolution by reconstructing fluorescence volumes from observations of multiple particle replicates with different orientation ...

IEEE2016

Reconstruction From Multiple Poses in Fluorescence Imaging: Proof of Concept

Michaël Unser, Paul Guichard, Ning Chu, Denis Fortun

One disadvantage of all fluorescence imaging modalities is a poor axial resolution. To overcome this issue, we propose a novel approach to reconstruct fluorescence volumes with isotropic high resolution, from images of particle replicates observed at multi ...

Ieee-Inst Electrical Electronics Engineers Inc2016

SAS-6 engineering reveals interdependence between cartwheel and microtubules in determining centriole architecture

Pierre Gönczy, Virginie Hamel, Paul Guichard

Centrioles are critical for the formation of centrosomes, cilia and flagella in eukaryotes. They are thought to assemble around a nine-fold symmetric cartwheel structure established by SAS-6 proteins. Here, we have engineered Chlamydomonas reinhardtii SAS- ...

Nature Publishing Group2016

The Human Centriolar Protein CEP135 Contains a Two-Stranded Coiled-Coil Domain Critical for Microtubule Binding

Pierre Gönczy, Paul Guichard, Georgios Hatzopoulos

Centrioles are microtubule-based structures that play important roles notably in cell division and cilium biogenesis. CEP135/Bld10p family members are evolutionarily conserved microtubule-binding proteins important for centriole formation. Here, we analyze ...

Elsevier2016

Computational support for a scaffolding mechanism of centriole assembly

Pierre Gönczy, Virginie Hamel, Paul Guichard

Centrioles are essential for forming cilia, flagella and centrosomes. Successful centriole assembly requires proteins of the SAS-6 family, which can form oligomeric ring structures with ninefold symmetry in vitro. While important progress has been made in ...

Nature Research2016

Basal body structure in Trichonympha

Pierre Gönczy, Paul Guichard

Trichonympha is a symbiotic flagellate of many species of termites and of the wood-feeding cockroach. Remarkably, this unicellular organism harbors up to over ten thousand flagella on its surface, which serve to propel it through the viscous environment of ...

Springer Nature2016

Direct visualization of dispersed lipid bicontinuous cubic phases by cryo-electron tomography

Raffaele Mezzenga, Davide Demurtas, Cécile Hébert, Paul Guichard

Bulk and dispersed cubic liquid crystalline phases (cubosomes), present in the body and in living cell membranes, are believed to play an essential role in biological phenomena. Moreover, their biocompatibility is attractive for nutrient or drug delivery s ...

Nature Publishing Group2015

Purification of centrosomes from mammalian cell lines

Paul Guichard

Centrosomes act as the main microtubule-organizing centre of animal cells and play critical roles in the cell, such as mitotic spindle organization, cell polarity, and motility. They are composed of two barrel-shaped structures, the centrioles, surrounded ...

Elsevier Academic Press Inc2015

Correlative multicolor 3D SIM and STORM microscopy

Mathias Fournier, Pierre Gönczy, Virginie Hamel, Arne Seitz, Isabelle Fluckiger, Paul Guichard, Romain Guiet

Within the last decade, super-resolution methods that surpass the diffraction limit of light microscopy have provided invaluable insight into a variety of biological questions. Each of these approaches has inherent advantages and limitations, such that the ...

Optical Soc Amer2014