Visualization and force measurement of branching by Arp2/3 complex and N-WASP in actin filament

Ikuko Fujiwara, Shiro Suetsugu, Sotaro Uemura, Tadaomi Takenawa, Shin'ichi Ishiwata*


    研究成果: Article査読

    47 被引用数 (Scopus)


    To determine whether the Arp2/3 complex activated by N-WASP (VCA) branches actin filaments at the side (side branching), or at the barbed (B-)end (end branching) of the mother filaments, we have directly observed the branching process of actin filaments and examined single-molecule unbinding under optical microscope. We found that side branching was predominant, though not exclusive. At the initial stage of polymerization, the branching at the B-end occurred and subsequently the side branching started to occur. In either type of branching, the mother and daughter filaments elongated at nearly the same rate (growing type). Independently of the stage of polymerization, branching due to the direct coupling of filaments with an acute angle to the mother filaments (a coupling type) occurred. Phalloidin suppressed the growing type of branching but not the coupling type, implying that actin monomers are required for the former but not the latter. We found, by single molecule measurements using optical tweezers, that the Arp2/3 complex attaches to the side of actin filaments and the N-WASP appears to detach from the actin-Arp2/3 complex at 6-7 pN.

    ジャーナルBiochemical and Biophysical Research Communications
    出版ステータスPublished - 2002

    ASJC Scopus subject areas

    • 生化学
    • 生物理学
    • 分子生物学


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