UNC-87, a calponin-related protein in C. elegans, antagonizes ADF/cofilin-mediated actin filament dynamics

Sawako Yamashiro, Mario Gimona, Shoichiro Ono

    Research output: Contribution to journalArticlepeer-review

    24 Citations (Scopus)


    Stabilization of actin filaments is critical for supporting actomyosin-based contractility and for maintaining stable cellular structures. Tropomyosin is a well-characterized ubiquitous actin stabilizer that inhibits ADF/cofflin-dependent actin depolymerization. Here, we show that UNC-87, a calponin-related Caenorhabditis elegans protein with seven calponin-like repeats, competes with ADF/cofilin for binding to actin filaments and inhibits ADF/cofilin-dependent filament severing and depolymerization in vitro. Mutations in the unc-87 gene suppress the disorganized actin phenotype in an ADF/cofilin mutant in the C. elegans body wall muscle, supporting their antagonistic roles in regulating actin stability in vivo. UNC-87 and tropomyosin exhibit synergistic effects in stabilizing actin filaments against ADF/cofilin, and direct comparison reveals that UNC-87 effectively stabilizes actin filaments at much lower concentrations than tropomyosin. However, the in vivo functions of UNC-87 and tropomyosin appear different, suggesting their distinct roles in the regulation of actomyosin assembly and cellular contractility. Our results demonstrate that actin binding via calponin-like repeats competes with ADF/cofilin-driven cytoskeletal turnover, and is critical for providing the spatiotemporal regulation of actin filament stability.

    Original languageEnglish
    Pages (from-to)3022-3033
    Number of pages12
    JournalJournal of cell science
    Issue number17
    Publication statusPublished - 2007 Sep 1


    • ADF/cofilin
    • Actin dynamics
    • Calponin
    • Tropomyosin

    ASJC Scopus subject areas

    • Cell Biology


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