Syndapins integrate N-WASP in receptor-mediated endocytosis.
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.
Kessels
Michael M
MM
Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Brenneckestrasse 6, D-39118 Magdeburg, Germany.
Qualmann
Britta
B
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001704:Biopolymers; D019556:COS Cells / Q000502:physiology / Q000648:ultrastructure; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured / Q000502:physiology / Q000648:ultrastructure; D002522:Chlorocebus aethiops; D003034:Coated Pits, Cell-Membrane / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000502:physiology; D003599:Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D034281:Dynamins / Q000502:physiology; D004705:Endocytosis / Q000502:physiology*; D017930:Genes, Reporter; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D011392:Proline / Q000737:chemistry; D025941:Protein Interaction Mapping; D020033:Protein Isoforms / Q000235:genetics / Q000502:physiology*; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000502:physiology; D012441:Saccharomyces cerevisiae; D014162:Transfection; D020798:Two-Hybrid System Techniques; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D018909:src Homology Domains
C495926:ACTR2 protein, human; C495928:ACTR3 protein, human; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D001704:Biopolymers; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins; C492182:PACSIN1 protein, human; C117738:Pacsin1 protein, rat; C492181:Pacsin2 protein, rat; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; C495771:WASL protein, human; C495770:Wasl protein, rat; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D011392:Proline; D034281:Dynamins