Abstract
N-WASP induces filopodial actin cytoskeleton through activation of the Arp2/3 complex. Here, we show that heat shock protein 90 (HSP90) regulates the structure of actin filaments induced by N-WASP and the Arp2/3 complex. HSP90 binds to N-WASP and to F-actin and bundles actin filaments. Bundling activity of HSP90 does not affect actin filament nucleation induced by N-WASP and the Arp2/3 complex. HSP90 is co-localized with N-WASP at branching points of actin filaments produced by the Arp2/3 complex and thereby bundles branched filaments; this bundled actin structure is inhibited by blocking direct binding between HSP90 and N-WASP. Furthermore, HSP90 converts branched actin filaments on N-WASP-coated beads to filopodia-like star-shaped bundles. These findings indicate that HSP90 promotes the formation of N-WASP/Arp2/3 complex-induced unbranched filopodial actin structures.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Actin-Related Protein 2-3 Complex / chemistry
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Actin-Related Protein 2-3 Complex / metabolism*
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Actins / chemistry
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Actins / metabolism*
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Actins / ultrastructure
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Animals
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Cattle
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Cell Line
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Cross-Linking Reagents
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HSP90 Heat-Shock Proteins / chemistry
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HSP90 Heat-Shock Proteins / metabolism*
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HSP90 Heat-Shock Proteins / ultrastructure
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In Vitro Techniques
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Kinetics
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Microscopy, Electron
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Multiprotein Complexes
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Protein Binding
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Rabbits
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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Recombinant Proteins / ultrastructure
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Wiskott-Aldrich Syndrome Protein, Neuronal / chemistry
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Wiskott-Aldrich Syndrome Protein, Neuronal / metabolism*
Substances
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Actin-Related Protein 2-3 Complex
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Actins
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Cross-Linking Reagents
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HSP90 Heat-Shock Proteins
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Multiprotein Complexes
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Recombinant Proteins
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Wiskott-Aldrich Syndrome Protein, Neuronal