Distributed actin turnover in the lamellipodium and FRAP kinetics

Matthew B. Smith, Tai Kiuchi, Naoki Watanabe, Dimitrios Vavylonis

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    22 Citations (Scopus)

    Abstract

    Studies of actin dynamics at the leading edge of motile cells with single-molecule speckle (SiMS) microscopy have shown a broad distribution of EGFP-actin speckle lifetimes and indicated actin polymerization and depolymerization over an extended region. Other experiments using FRAP with the same EGFP-actin as a probe have suggested, by contrast, that polymerization occurs exclusively at the leading edge. We performed FRAP experiments on XTC cells to compare SiMS to FRAP on the same cell type. We used speckle statistics obtained by SiMS to model the steady-state distribution and kinetics of actin in the lamellipodium. We demonstrate that a model with a single diffuse actin species is in good agreement with FRAP experiments. A model including two species of diffuse actin provides an even better agreement. The second species consists of slowly diffusing oligomers that associate to the F-actin network throughout the lamellipodium or break up into monomers after a characteristic time. Our work motivates studies to test the presence and composition of slowly diffusing actin species that may contribute to local remodeling of the actin network and increase the amount of soluble actin.

    Original languageEnglish
    Pages (from-to)247-257
    Number of pages11
    JournalBiophysical Journal
    Volume104
    Issue number1
    DOIs
    Publication statusPublished - 2013 Jan 8

    ASJC Scopus subject areas

    • Biophysics

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  • Cite this

    Smith, M. B., Kiuchi, T., Watanabe, N., & Vavylonis, D. (2013). Distributed actin turnover in the lamellipodium and FRAP kinetics. Biophysical Journal, 104(1), 247-257. https://doi.org/10.1016/j.bpj.2012.11.3819