Abstract
Metastasizing tumor cells use matrix metalloproteases, such as the transmembrane collagenase MT1-MMP, together with actin-based protrusions, to break through extracellular matrix barriers and migrate in dense matrix. Here we show that the actin nucleation-promoting protein N-WASP (Neural Wiskott-Aldrich syndrome protein) is up-regulated in breast cancer, and has a pivotal role in mediating the assembly of elongated pseudopodia that are instrumental in matrix degradation. Although a role for N-WASP in invadopodia was known, we now show how N-WASP regulates invasive protrusion in 3D matrices. In actively invading cells, N-WASP promoted trafficking of MT1-MMP into invasive pseudopodia, primarily from late endosomes, from which it was delivered to the plasma membrane. Upon MT1-MMP's arrival at the plasma membrane in pseudopodia, N-WASP stabilized MT1-MMP via direct tethering of its cytoplasmic tail to F-actin. Thus, N-WASP is crucial for extension of invasive pseudopods into which MT1-MMP traffics and for providing the correct cytoskeletal framework to couple matrix remodeling with protrusive invasion.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Actin Cytoskeleton / metabolism
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Actins / metabolism*
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Adenocarcinoma / metabolism
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Adenocarcinoma / pathology
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Animals
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Blotting, Western
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Breast / metabolism
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Breast Neoplasms / metabolism*
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Breast Neoplasms / pathology*
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Carcinoma, Ductal, Breast / metabolism
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Carcinoma, Ductal, Breast / pathology
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Carcinoma, Intraductal, Noninfiltrating / metabolism
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Carcinoma, Intraductal, Noninfiltrating / pathology
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Cell Membrane / metabolism
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Cell Movement / physiology*
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Extracellular Matrix / metabolism
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Female
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Fluorescence Resonance Energy Transfer
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Fluorescent Antibody Technique
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Humans
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Immunoenzyme Techniques
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Matrix Metalloproteinase 14 / metabolism*
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Mice
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Neoplasm Invasiveness
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Protein Multimerization
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Protein Transport
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Pseudopodia / metabolism
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Pseudopodia / pathology*
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RNA, Messenger / genetics
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RNA, Small Interfering / genetics
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Tumor Cells, Cultured
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Wiskott-Aldrich Syndrome Protein, Neuronal / antagonists & inhibitors
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Wiskott-Aldrich Syndrome Protein, Neuronal / genetics
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Wiskott-Aldrich Syndrome Protein, Neuronal / metabolism*
Substances
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Actins
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RNA, Messenger
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RNA, Small Interfering
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Wiskott-Aldrich Syndrome Protein, Neuronal
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Matrix Metalloproteinase 14