Actin turnover-dependent fast dissociation of capping protein in the dendritic nucleation actin network: Evidence of frequent filament severing

Takushi Miyoshi, Takahiro Tsuji, Chiharu Higashida, Maud Hertzog, Akiko Fujita, Shuh Narumiya, Giorgio Scita, Naoki Watanabe

    研究成果: Article査読

    86 被引用数 (Scopus)

    抄録

    Actin forms the dendritic nucleation network and undergoes rapid polymerization-depolymerization cycles in lamellipodia. To elucidate the mechanism of actin disassembly, we characterized molecular kinetics of the major filament end-binding proteins Arp2/3 complex and capping protein (CP) using single-molecule speckle microscopy. We have determined the dissociation rates of Arp2/3 and CP as 0.048 and 0.58 s-1, respectively, in lamellipodia of live XTC fibroblasts. This CP dissociation rate is three orders of magnitude faster than in vitro. CP dissociates slower from actin stress fibers than from the lamellipodial actin network, suggesting that CP dissociation correlates with actin filament dynamics. We found that jasplakinolide, an actin depolymerization inhibitor, rapidly blocked the fast CP dissociation in cells. Consistently, the coexpression of LIM kinase prolonged CP speckle lifetime in lamellipodia. These results suggest that cofilin-mediated actin disassembly triggers CP dissociation from actin filaments. We predict that filament severing and end-to-end annealing might take place fairly frequently in the dendritic nucleation actin arrays.

    本文言語English
    ページ(範囲)947-955
    ページ数9
    ジャーナルJournal of Cell Biology
    175
    6
    DOI
    出版ステータスPublished - 2006 12 18

    ASJC Scopus subject areas

    • Cell Biology

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