Actin-filament cross-linking protein T-plastin increases Arp2/3-mediated actin-based movement.
Increasing evidence suggests that actin cross-linking or bundling proteins might not only structure the cortical actin cytoskeleton but also control actin dynamics. Here, we analyse the effects of T-plastin/T-fimbrin, a representative member of an important actin-filament cross-linking protein by combining a quantitative biomimetic motility assay with biochemical and cell-based approaches. Beads coated with the VCA domain of the Wiskott/Aldrich-syndrome protein (WASP) recruit the actin-nucleating Arp2/3 complex, polymerize actin at their surface and undergo movement when placed in cell-free extracts. T-Plastin increased the velocity of VCA beads 1.5 times, stabilized actin comets and concomitantly displaced cofilin, an actin-depolymerizing protein. T-Plastin also decreased the F-actin disassembly rate and inhibited cofilin-mediated depolymerization of actin filaments in vitro. Importantly, a bundling-incompetent variant comprising the first actin-binding domain (ABD1) had similar effects. In cells, this domain induced the formation of long actin cables to which other actin-regulating proteins were recruited. Altogether, these results favor a mechanism in which binding of ABD1 controls actin turnover independently of cross-link formation. In vivo, this activity might contribute to the assembly and maintenance of the actin cytoskeleton of plasma-membrane protrusions.
Giganti
Adeline
A
Laboratoire de Biologie Moléculaire, d'Analyse Génique et de Modélisation, Centre de Recherche Public-Santé, 42, rue du Laboratoire, L-1911, Luxembourg.
Plastino
Julie
J
Janji
Bassam
B
Van Troys
Marleen
M
Lentz
Delphine
D
Ampe
Christophe
C
Sykes
Cécile
C
Friederich
Evelyne
E
D008841:Actin Cytoskeleton / Q000737:chemistry*; D051339:Actin Depolymerizing Factors; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002474:Cell-Free System; D002522:Chlorocebus aethiops; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004247:DNA / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast; D009363:Neoplasm Proteins / Q000737:chemistry; D010750:Phosphoproteins / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D014709:Vero Cells; D051316:Wiskott-Aldrich Syndrome Protein
C495926:ACTR2 protein, human; C495928:ACTR3 protein, human; D051339:Actin Depolymerizing Factors; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D000911:Antibodies, Monoclonal; D003432:Cross-Linking Reagents; D003598:Cytoskeletal Proteins; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D009363:Neoplasm Proteins; D010750:Phosphoproteins; D011506:Proteins; C495767:WAS protein, human; D051316:Wiskott-Aldrich Syndrome Protein; C026742:plastin; D004247:DNA; D002118:Calcium