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Mallet, A.

Publications and source records attributed to Mallet, A..

2 recordsLinked to original sources

Adhesion to nanofibers drives cell membrane remodeling through 1D wetting

The shape of cellular membranes is highly regulated by a set of conserved mechanisms. These mechanisms can be manipulated by bacterial pathogens to infect cells. Human endothelial cell plasma membrane remodeling by the bacterium Neisseria meningitidis is thought to be essential during the blood phase of meningococcal infection, but the underlying mechanisms are unknown. Here we show that plasma membrane remodeling occurs independently of F-actin, along meningococcal type IV pili fibers, by a novel physical mechanism we term \" onedimensional\" membrane wetting. We provide a theoretical model that gives the physical basis of 1D wetting and show that this mechanism occurs in model membranes interacting with model nanofibers, and in human cells interacting with model extracellular matrices. It is thus a new general principle driving the interaction of cells with their environment at the nanoscale that is diverted by meningococcus during infection.

cell biology

Bidirectional intraflagellar transport is restricted to only two microtubule doublets in the trypanosome flagellum

Intraflagellar transport (IFT) is the rapid bidirectional movement of large protein complexes driven by kinesin and dynein motors along microtubule doublets of cilia and flagella. Here we used a combination of high-resolution electron and light microscopy to investigate how and where these IFT trains move within the flagellum of the protist Trypanosoma brucei. Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) analysis of trypanosomes showed that trains are found almost exclusively along two sets of doublets (3-4 and 7-8) and distribute in two categories according to their length. High-resolution live imaging of cells expressing mNeonGreen::IFT81 or GFP::IFT52 revealed for the first time IFT trafficking on two parallel lines within the flagellum. Anterograde and retrograde IFT occur on each of these lines. At the distal end, a large individual anterograde IFT train is converted in several smaller retrograde trains in the space of 3-4 seconds while remaining on the same side of the axoneme.

cell biology