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Updated: Apr 15, 2026

Using Microfluidics and Fluorescence Microscopy to Study the Assembly Dynamics of Single Actin Filaments and Bundles
Published on: May 5, 2022
Dimeric WH2 repeats of VopF sequester actin monomers into non-nucleating linear string conformations: An X-ray
Balendu Sankara Avvaru1, Julien Pernier1, Marie-France Carlier1
1Cytoskeleton Dynamics and Motility Group, CNRS, Gif-sur-Yvette, France.
Abstract:
VopF and VopL are highly similar virulence-factors of Vibrio cholerae and Vibrio parahaemolyticus respectively that disrupt the host's actin cytoskeleton, using a unique organization in dimerized WH2 repeats. Association of dimerized WH2 domains with the barbed face of actin confers multifunctional activities to VopF in vitro, including G-actin sequestration and filament nucleation, barbed end tracking and uncapping. Here, small angle X-ray scattering (SAXS) measurements of complexes of VopF with actin and structural modeling reveal that VopF stabilizes linear actin-strings that differ from canonical actin filament architectures but represent non-polymerizable sequestered forms of actin. The results exclude that VopL binds the pointed end of actin filaments in the template filament nucleation mechanism derived from crystallographic studies.
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