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Journal of Cellular Biochemistry

Cytoskeletal protein vimentin interacts with and regulates peroxisome proliferator-activated receptor gamma via a proteasomal degradation process

Authors

  • Yun-Chih Tsai,

    1. Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
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  • Shu-Huei Tsai,

    1. Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
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  • Emily Yun-Chia Chang,

    1. Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
    2. Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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  • Siow-Wey Hee,

    1. Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
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  • Wei-Hao Chen,

    1. Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
    2. Institute of Atomic and Molecular Sciences, Academia Sinica Taipei, Taiwan
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  • Sheng-Chung Lee,

    1. Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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  • Dr. Lee-Ming Chuang

    Corresponding author
    1. Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
    2. Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
    3. Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
    • Department of Internal Medicine, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei, Taiwan.
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Abstract

Peroxisome proliferators-activated receptor gamma (PPARγ) receptor is a transcription factor that is located in and functions primarily in the nucleus. PPARγ is exported from the nucleus upon mitogen and ligand stimulation under certain circumstances. However, a cytoplasmic PPARγ interacting protein and its function have not been previously identified. Here, we report for the first time that cytosolic PPARγ interacts directly with cytoskeletal vimentin. We performed PPARγ immunoprecipitation followed by mass spectrometry to identify the vimentin-PPARγ complex. This interaction was confirmed by reciprocal vimentin and PPARγ immunoprecipitation and co-immunofluorescence examination. We demonstrated that PPARγ colocalized with vimentin in certain organelles that is golgi, mitochondria, and endoplasmic reticulum. In cells depleted of vimentin, PPARγ was ubiquitinated and targeted to a proteasomal degradation pathway. Together, these findings indicate a direct interaction of PPARγ with vimentin in the cytosolic compartment, in which vimentin appears to play a role in regulating the turnover rate of PPARγ, which may further regulate genomic or non-genomic activities through the regulation of PPARγ protein degradation. J. Cell. Biochem. 114: 1559–1567, 2013. © 2013 Wiley Periodicals, Inc.

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