Abstract
Mammarian enabled (Mena), a member of the Enabled (Ena)/Vasodilator-stimulated phosphoprotein (VASP) family of proteins, has been implicated in cell motility through regulation of the actin cytoskeleton assembly, including lamellipodial protrusion. Rac1, a member of the Rho family GTPases, also plays a pivotal role in the formation of lamellipodia. Here we report that human Mena (hMena) colocalizes with Rac1 in lamellipodia, and using an unmixing assisted acceptor depletion fluorescence resonance energy transfer (u-adFRET) analysis that hMena associates with Rac1 in vivo in the glioblastoma cell line U251MG. Depletion of hMena by siRNA causes cells to be highly spread with the formation of lamellipodia. This cellular phenotype is canceled by introduction of a dominant negative form of Rac1. A Rac activity assay and FRET analysis showed that hMena knock-down cells increased the activation of Rac1 at the lamellipodia. These results suggest that hMena possesses properties which help to regulate the formation of lamellipodia through the modulation of the activity of Rac1.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Brain Neoplasms / chemistry
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Brain Neoplasms / pathology*
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Cell Line, Tumor / chemistry
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Cell Line, Tumor / ultrastructure
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Cell Movement
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Cell Shape
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Fluorescence Resonance Energy Transfer
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Glioblastoma / chemistry
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Glioblastoma / pathology*
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HeLa Cells / chemistry
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HeLa Cells / ultrastructure
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Humans
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Microfilament Proteins / antagonists & inhibitors
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Microfilament Proteins / chemistry
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Microfilament Proteins / genetics
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Microfilament Proteins / physiology*
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Neoplasm Proteins / antagonists & inhibitors
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Neoplasm Proteins / chemistry
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Neoplasm Proteins / genetics
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Neoplasm Proteins / physiology*
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Protein Interaction Mapping
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Pseudopodia / chemistry*
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Pseudopodia / ultrastructure
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RNA Interference
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RNA, Small Interfering / pharmacology
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / physiology
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Signal Transduction
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rac1 GTP-Binding Protein / chemistry
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rac1 GTP-Binding Protein / physiology*
Substances
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Enah protein, human
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Microfilament Proteins
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Neoplasm Proteins
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RAC1 protein, human
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RNA, Small Interfering
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Recombinant Fusion Proteins
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rac1 GTP-Binding Protein