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Polarized actin bundles formed by human fascin‐1: their sliding and disassembly on myosin II and myosin V in vitro
Author(s) -
Ishikawa Ryoki,
Sakamoto Takeshi,
Ando Toshio,
HigashiFujime Sugie,
Kohama Kazuhiro
Publication year - 2003
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2003.02058.x
Subject(s) - fascin , filopodia , myosin , bundle , heavy meromyosin , actin , microbiology and biotechnology , myosin head , microfilament , actin remodeling of neurons , biophysics , pseudopodia , mdia1 , biology , chemistry , materials science , cytoskeleton , myosin light chain kinase , cell , biochemistry , composite material
Fascin‐1 is a putative bundling factor of actin filaments in the filopodia of neuronal growth cones. Here, we examined the structure of the actin bundle formed by human fascin‐1 (actin/fascin bundle), and its mode of interaction with myosin in vitro . The distance between cross‐linked filaments in the actin/bundle was 8–9 nm, and the bundle showed the transverse periodicity of 36 nm perpendicular to the bundle axis, which was confirmed by electron microscopy. Decoration of the actin/fascin bundle with heavy meromyosin revealed that the arrowheads of filaments in the bundle pointed in the same direction, indicating that the bundle has polarity. This result suggested that fascin‐1 plays an essential role in polarity of actin bundles in filopodia. In the in vitro motility assay, actin/fascin bundles slid as fast as single actin filaments on myosin II and myosin V. When myosin was attached to the surface at high density, the actin/fascin bundle disassembled to single filaments at the pointed end of the bundle during sliding. These results suggest that myosins may drive filopodial actin bundles backward by interacting with actin filaments on the surface, and may induce disassembly of the bundle at the basal region of filopodia.