Abstract
Cell-substrate contacts, called focal adhesions (FAs), are dynamic in rapidly moving cells. We show that supervillin (SV)--a peripheral membrane protein that binds myosin II and F-actin in such cells--negatively regulates stress fibers, FAs, and cell-substrate adhesion. The major FA regulatory sequence within SV (SV342-571) binds to the LIM domains of two proteins in the zyxin family, thyroid receptor-interacting protein 6 (TRIP6) and lipoma-preferred partner (LPP), but not to zyxin itself. SV and TRIP6 colocalize within large FAs, where TRIP6 may help recruit SV. RNAi-mediated decreases in either protein increase cell adhesion to fibronectin. TRIP6 partially rescues SV effects on stress fibers and FAs, apparently by mislocating SV away from FAs. Thus, SV interactions with TRIP6 at FAs promote loss of FA structure and function. SV and TRIP6 binding partners suggest several specific mechanisms through which the SV-TRIP6 interaction may regulate FA maturation and/or disassembly.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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ATPases Associated with Diverse Cellular Activities
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Adaptor Proteins, Signal Transducing / chemistry
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Adaptor Proteins, Signal Transducing / metabolism*
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Animals
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COS Cells
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Cattle
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Cells, Cultured
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Chlorocebus aethiops
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Down-Regulation / genetics
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Focal Adhesions / metabolism*
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Green Fluorescent Proteins / metabolism
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Humans
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LIM Domain Proteins
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Membrane Proteins / metabolism*
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Mice
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Microfilament Proteins / metabolism*
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Microtubule-Associated Proteins / metabolism
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Myocytes, Smooth Muscle / cytology
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Nuclear Proteins / metabolism
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Proteasome Endopeptidase Complex
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Protein Binding
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Rats
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Regulatory Sequences, Nucleic Acid / genetics
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Transcription Factors / chemistry
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Transcription Factors / metabolism*
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t-Complex Genome Region
Substances
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Adaptor Proteins, Signal Transducing
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LIM Domain Proteins
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Membrane Proteins
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Microfilament Proteins
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Microtubule-Associated Proteins
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Nuclear Proteins
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PSMC5 protein, human
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Transcription Factors
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enhanced green fluorescent protein
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Green Fluorescent Proteins
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Proteasome Endopeptidase Complex
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ATPases Associated with Diverse Cellular Activities