A WASp-VASP complex regulates actin polymerization at the plasma membrane.
Proteins of the Wiskott-Aldrich syndrome and Ena/VASP families both play essential functions in the regulation of actin dynamics at the cell leading edge. However, possibilities of functional interplay between members of these two families have not been addressed. Here we show that, in hemopoietic cells, recruitment of the C-terminal VCA (Verprolin homology, Cofilin homology, Acidic) domain of WASp at the plasma membrane by a ligand technique using rapamycin as an intermediate is not sufficient to elicit efficient Arp2/3 complex-mediated actin polymerization. Other domains of WASp, in particular the proline-rich domain, are required for the formation of actin-rich structures. An in vitro analysis demonstrates that the proline-rich domain of WASp binds VASP with an affinity of approximately 10(6) M(-1). In addition, WASp and VASP both accumulate in actin-rich phagocytic cups. Finally, in a reconstituted motility medium, VASP enhances actin-based propulsion of WASp-coated beads in a fashion reminiscent of its effect on Listeria movement. We propose that VASP and WASp cooperation is essential in stimulating actin assembly and membrane protrusion at the leading edge.
Castellano
F
F
Laboratoire de la Dynamique de la Membrane et du Cytosquelette, Centre National de la Recherche Scientifique UMR 144, Institut Curie, 26 rue d'Ulm, 75241 Paris Cedex 5, France.
Le Clainche
C
C
Patin
D
D
Carlier
M F
MF
Chavrier
P
P
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001704:Biopolymers; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000502:physiology*; D002460:Cell Line; D002465:Cell Movement; D006224:Cricetinae; D003598:Cytoskeletal Proteins; D019281:Dimerization; D005455:Fluorescent Antibody Technique; D007668:Kidney; D015471:Leukemia, Basophilic, Acute / Q000473:pathology; D008024:Ligands; D046911:Macromolecular Substances; D008407:Mast Cells / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008647:Mesocricetus; D008840:Microfilament Proteins; D005810:Multigene Family; D010587:Phagocytosis; D010750:Phosphoproteins / Q000737:chemistry / Q000502:physiology*; D011392:Proline / Q000737:chemistry; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000502:physiology*; D051381:Rats; D015375:Receptors, Interleukin-2 / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020123:Sirolimus / Q000378:metabolism; D013329:Structure-Activity Relationship; D022021:Tacrolimus Binding Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D051316:Wiskott-Aldrich Syndrome Protein; D000098662:Vasodilator-Stimulated Phosphoprotein
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D001704:Biopolymers; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D008024:Ligands; D046911:Macromolecular Substances; D008565:Membrane Proteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D011506:Proteins; D015375:Receptors, Interleukin-2; D011993:Recombinant Fusion Proteins; C495769:Was protein, rat; D051316:Wiskott-Aldrich Syndrome Protein; D000098662:Vasodilator-Stimulated Phosphoprotein; D011392:Proline; D022021:Tacrolimus Binding Proteins; D020123:Sirolimus