Identification of intermediate filament protein vimentin as an interacting protein of PPARγ
碩士 === 國立臺灣大學 === 分子醫學研究所 === 96 === Peroxisome proliferators activated receptor gamma (PPARγ) is a ligand activated transcription factor of the nuclear receptor family that regulates genes involved in differentiation, metabolism and immunity. Upon ligand binding, PPARγ releases bound corepressors a...
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ndltd-TW-096NTU055380242015-11-25T04:04:25Z http://ndltd.ncl.edu.tw/handle/24554411528825991876 Identification of intermediate filament protein vimentin as an interacting protein of PPARγ 中間絲蛋白vimentin為PPARγ的結合蛋白之鑑定與研究 Yun-Chih Tsai 蔡昀芝 碩士 國立臺灣大學 分子醫學研究所 96 Peroxisome proliferators activated receptor gamma (PPARγ) is a ligand activated transcription factor of the nuclear receptor family that regulates genes involved in differentiation, metabolism and immunity. Upon ligand binding, PPARγ releases bound corepressors and recruits coactivators for transcriptional activation. As a central signaling component, the activity of PPARγ is well regulated under various cellular processes. Mitogenic stimulation exerts negative regulation that suppresses PPARγ’s genomic activity. This downregulation is mediated largely by the extracellular signal regulated kinase 1/2 (ERKs)/mitogen activated protein kinases (MAPKs) signaling cascade. Upon mitogen and ligand stimulation, MEKs and ERKs rapidly translocate into the nucleus followed by ERK-mediated PPARγ phosphorylation on Serine 82/112. Upon binding onto the phosphorylated PPARγ, the NES in the MEKs then mediated the export of phosphorylated PPARγ out of the nucleus. This massive nuclear export reduces the ability of PPARγ to transactivate nuclear target genes and thereby inhibits its genomic function. However, the exact mechanism of nuclear export of PPARγ and the subsequent fate of cytoplasmic PPARγ remain further elucidated. With advent of LC/MS/MS technique, we have identified a protein vimentin which was associated with PPARγ from the cell extracts of 3T3-L1 adipocytes upon induction of differentiation. During adipocyte differentiation, the expression of vimentin was increased in parallel of the increases of PPARγ. We confirmed the association of vimentin and PPARγ in the cytoplasmic compartment of 3T3-L1 adipocytes with immunoprecipitation-western blot and immunocytochemistry studies. Interestingly, vimentin was preferentially associated with the phospho-PPARγ especially after treatment of PPARγ ligand. Our data also suggest that phosphorylation of PPARγ appears after ligand treatment which leads to subsequent export of phosphorylated PPARγ to cytoplasm, at a leptomycin B-sensitive exportin 1/CRM1 dependent pathway, where interaction with vimentin occurs. Further detailed studies showed that the interaction of vimentin and pPPARγ may take place in mitochondria and ER in addition to the expected cytoskeleton in the insoluble portion of cell extracts. Lee-Ming Chuang 莊立民 2008 學位論文 ; thesis 57 en_US |
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碩士 === 國立臺灣大學 === 分子醫學研究所 === 96 === Peroxisome proliferators activated receptor gamma (PPARγ) is a ligand activated transcription factor of the nuclear receptor family that regulates genes involved in differentiation, metabolism and immunity. Upon ligand binding, PPARγ releases bound corepressors and recruits coactivators for transcriptional activation. As a central signaling component, the activity of PPARγ is well regulated under various cellular processes. Mitogenic stimulation exerts negative regulation that suppresses PPARγ’s genomic activity. This downregulation is mediated largely by the extracellular signal regulated kinase 1/2 (ERKs)/mitogen activated protein kinases (MAPKs) signaling cascade. Upon mitogen and ligand stimulation, MEKs and ERKs rapidly translocate into the nucleus followed by ERK-mediated PPARγ phosphorylation on Serine 82/112. Upon binding onto the phosphorylated PPARγ, the NES in the MEKs then mediated the export of phosphorylated PPARγ out of the nucleus. This massive nuclear export reduces the ability of PPARγ to transactivate nuclear target genes and thereby inhibits its genomic function. However, the exact mechanism of nuclear export of PPARγ and the subsequent fate of cytoplasmic PPARγ remain further elucidated.
With advent of LC/MS/MS technique, we have identified a protein vimentin which was associated with PPARγ from the cell extracts of 3T3-L1 adipocytes upon induction of differentiation. During adipocyte differentiation, the expression of vimentin was increased in parallel of the increases of PPARγ. We confirmed the association of vimentin and PPARγ in the cytoplasmic compartment of 3T3-L1 adipocytes with immunoprecipitation-western blot and immunocytochemistry studies. Interestingly, vimentin was preferentially associated with the phospho-PPARγ especially after treatment of PPARγ ligand.
Our data also suggest that phosphorylation of PPARγ appears after ligand treatment which leads to subsequent export of phosphorylated PPARγ to cytoplasm, at a leptomycin B-sensitive exportin 1/CRM1 dependent pathway, where interaction with vimentin occurs. Further detailed studies showed that the interaction of vimentin and pPPARγ may take place in mitochondria and ER in addition to the expected cytoskeleton in the insoluble portion of cell extracts.
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author2 |
Lee-Ming Chuang |
author_facet |
Lee-Ming Chuang Yun-Chih Tsai 蔡昀芝 |
author |
Yun-Chih Tsai 蔡昀芝 |
spellingShingle |
Yun-Chih Tsai 蔡昀芝 Identification of intermediate filament protein vimentin as an interacting protein of PPARγ |
author_sort |
Yun-Chih Tsai |
title |
Identification of intermediate filament protein vimentin as an interacting protein of PPARγ |
title_short |
Identification of intermediate filament protein vimentin as an interacting protein of PPARγ |
title_full |
Identification of intermediate filament protein vimentin as an interacting protein of PPARγ |
title_fullStr |
Identification of intermediate filament protein vimentin as an interacting protein of PPARγ |
title_full_unstemmed |
Identification of intermediate filament protein vimentin as an interacting protein of PPARγ |
title_sort |
identification of intermediate filament protein vimentin as an interacting protein of pparγ |
publishDate |
2008 |
url |
http://ndltd.ncl.edu.tw/handle/24554411528825991876 |
work_keys_str_mv |
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