Abstract
Syndapins are potential links between the cortical actin cytoskeleton and endocytosis because this family of dynamin-associated proteins can also interact with the Arp2/3 complex activator N-WASP. Here we provide evidence for involvement of N-WASP interactions in receptor-mediated endocytosis. We reveal that the observed dominant-negative effects of N-WASP are dependent exclusively on the proline-rich domain, the binding interface of syndapins. Our results therefore suggest that syndapins integrate N-WASP functions in endocytosis. Both proteins co-localize in neuronal cells. Consistent with a crucial role for syndapins in endocytic uptake, co-overexpression of syndapins rescued the endocytosis block caused by N-WASP. An in vivo reconstitution of the syndapin-N-WASP interaction at cellular membranes triggered local actin polymerization. Depletion of endogenous N-WASP by sequestering it to mitochondria or by introducing anti-N-WASP antibodies impaired endocytosis. Our data suggest that syndapins may act as important coordinators of N-WASP and dynamin functions during the different steps of receptor-mediated endocytosis and that local actin polymerization induced by syndapin-N-WASP interactions may be a mechanism supporting clathrin-coated vesicle detachment and movement away from the plasma membrane.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Actin-Related Protein 2
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Actin-Related Protein 3
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Actins / metabolism
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Adaptor Proteins, Signal Transducing
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Animals
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Biopolymers
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COS Cells / physiology
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COS Cells / ultrastructure
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Carrier Proteins / genetics
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Carrier Proteins / physiology*
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Cells, Cultured / physiology
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Cells, Cultured / ultrastructure
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Chlorocebus aethiops
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Coated Pits, Cell-Membrane / physiology*
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Cytoskeletal Proteins / physiology
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Cytoskeleton / metabolism
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Cytoskeleton / ultrastructure
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Dynamins / physiology
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Endocytosis / physiology*
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Genes, Reporter
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Hippocampus / cytology
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Humans
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Macromolecular Substances
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / physiology*
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Neurons / physiology*
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Proline / chemistry
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Protein Interaction Mapping
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Protein Isoforms / genetics
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Protein Isoforms / physiology*
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Protein Structure, Tertiary
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Rats
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Recombinant Fusion Proteins / physiology
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Saccharomyces cerevisiae
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Transfection
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Two-Hybrid System Techniques
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Wiskott-Aldrich Syndrome Protein, Neuronal
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src Homology Domains
Substances
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ACTR2 protein, human
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ACTR3 protein, human
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Actin-Related Protein 2
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Actin-Related Protein 3
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Actins
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Adaptor Proteins, Signal Transducing
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Biopolymers
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Carrier Proteins
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Cytoskeletal Proteins
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Macromolecular Substances
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Nerve Tissue Proteins
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PACSIN1 protein, human
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Pacsin1 protein, rat
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Pacsin2 protein, rat
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Protein Isoforms
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Recombinant Fusion Proteins
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WASL protein, human
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Wasl protein, rat
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Wiskott-Aldrich Syndrome Protein, Neuronal
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Proline
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Dynamins