Alexis Gautreau

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The Arp2/3 complex generates branched actin networks when activated by Nucleation Promoting Factors (NPFs). Recently, the WASH family of NPFs has been identified, but its cellular role is unclear. Here, we show that WASH generates an actin network on a restricted domain of sorting and recycling endosomes. We found that WASH belongs to a multiprotein complex(More)
ERM (ezrin, radixin, moesin) proteins act as linkers between the plasma membrane and the actin cytoskeleton. An interaction between their NH(2)- and COOH-terminal domains occurs intramolecularly in closed monomers and intermolecularly in head-to-tail oligomers. In vitro, phosphorylation of a conserved threonine residue (T567 in ezrin) in the COOH-terminal(More)
Ezrin, a membrane-actin cytoskeleton linker, which participates in epithelial cell morphogenesis, is held inactive in the cytoplasm through an intramolecular interaction. Phosphatidylinositol 4,5-bisphosphate (PIP2) binding and the phosphorylation of threonine 567 (T567) are involved in the activation process that unmasks both membrane and actin binding(More)
The Wave proteins are major activators of the Arp2/3 complex. The ubiquitous Wave-2 is required for actin polymerization at the leading edge of migrating cells. Here we purify Wave-2 from HeLa cells. Five proteins, Sra, Nap, Wave-2, Abi, and Hspc, are copurified, indicating that they form a tight complex. These proteins are only present in the complexed(More)
The dissociation, migration, and remodeling of epithelial monolayers induced by hepatocyte growth factor (HGF) entail modifications in cell adhesion and in the actin cytoskeleton through unknown mechanisms. Here we report that ezrin, a membrane-cytoskeleton linker, is crucial to HGF-mediated morphogenesis in a polarized kidney-derived epithelial cell line,(More)
Endosomal protein sorting governs the fate of many physiologically important proteins involved in a panoply of cellular functions. Recent discoveries have revealed a vital role for endosomally localised branched actin patches in facilitating protein sorting. The formation of the actin patches has been shown to require the function of the WASH complex - the(More)
ERM (Ezrin-Radixin-Moesin) proteins function as plasma membrane-actin cytoskeleton linkers and participate in the formation of specialized domains of the plasma membrane. We have investigated ezrin function in tubulogenesis of a kidney-derived epithelial cell line, LLC-PK1. Here we show that cells overproducing a mutant form of ezrin in which Tyr-353 was(More)
Protein kinase C (PKC) alpha has been implicated in beta1 integrin-mediated cell migration. Stable expression of PKCalpha is shown here to enhance wound closure. This PKC-driven migratory response directly correlates with increased C-terminal threonine phosphorylation of ezrin/moesin/radixin (ERM) at the wound edge. Both the wound migratory response and ERM(More)
Remodeling of the extracellular matrix by carcinoma cells during metastatic dissemination requires formation of actin-based protrusions of the plasma membrane called invadopodia, where the trans-membrane type 1 matrix metalloproteinase (MT1-MMP) accumulates. Here, we describe an interaction between the exocyst complex and the endosomal Arp2/3 activator(More)
Cell and organelle shape can profoundly influence proper cellular function. In recent years, two machineries have emerged as major regulators of membrane shape: Bin-Amphiphysin-Rvs161/167 (BAR) domain-containing proteins, which induce membrane invaginations or protrusions, and nucleation promoting factors (NPFs), which activate the Arp2/3 complex and are(More)