title: Lamellipodin promotes actin assembly by clustering Ena/VASP proteins and tethering them to actin filaments.
abstract: Enabled/Vasodilator (Ena/VASP) proteins promote actin filament assembly at multiple locations, including: leading edge membranes, focal adhesions, and the surface of intracellular pathogens. One important Ena/VASP regulator is the mig-10/Lamellipodin/RIAM family of adaptors that promote lamellipod formation in fibroblasts and drive neurite outgrowth and axon guidance in neurons. To better understand how MRL proteins promote actin network formation we studied the interactions between Lamellipodin (Lpd), actin, and VASP, both in vivo and in vitro. We find that Lpd binds directly to actin filaments and that this interaction regulates its subcellular localization and enhances its effect on VASP polymerase activity. We propose that Lpd delivers Ena/VASP proteins to growing barbed ends and increases their polymerase activity by tethering them to filaments. This interaction represents one more pathway by which growing actin filaments produce positive feedback to control localization and activity of proteins that regulate their assembly.
authors: Department of Cellular and Molecular Pharmacology, University of California, San Francisco School of Medicine, San Francisco, United States.
authors: Scott D
authors: SD
authors: Hansen
authors: Department of Cellular and Molecular Pharmacology, University of California, San Francisco School of Medicine, San Francisco, United States.
authors: R Dyche
authors: RD
authors: Mullins
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization
chemical_list: D000199:Actins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C092744:ENA-VASP proteins; D008565:Membrane Proteins; C493339:RAPH1 protein, human
keywords: E. coli; TIRF microscropy; actin; biochemistry; cell biology; cytoskeleton; human; membrane; mouse; single molecule; xenopus