• Molecules and Cells
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• v.41 no.6
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• pp.562-574
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• 2018

The tazarotene-induced gene 1 (TIG1) protein is a retinoidinducible growth regulator and is considered a tumor suppressor. Here, we show that DnaJ heat shock protein family member C8 (DNAJC8) is a TIG1 target that regulates glycolysis. Ectopic DNAJC8 expression induced the translocation of pyruvate kinase M2 (PKM2) into the nucleus, subsequently inducing glucose transporter 1 (GLUT1) expression to promote glucose uptake. Silencing either DNAJC8 or PKM2 alleviated the upregulation of GLUT1 expression and glucose uptake induced by ectopic DNAJC8 expression. TIG1 interacted with DNAJC8 in the cytosol, and this interaction completely blocked DNAJC8-mediated PKM2 translocation and inhibited glucose uptake. Furthermore, increased glycose uptake was observed in cells in which TIG1 was silenced. In conclusion, TIG1 acts as a pivotal repressor of DNAJC8 to enhance glucose uptake by partially regulating PKM2 translocation.

• Biomolecules & Therapeutics
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• v.16 no.3
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• pp.197-202
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• 2008

In our previous publication we compared the gene expression profiles on hepatotoxicants exposure to assess the comparability between in vivo and in vitro test systems. We investigated global gene expression from both mouse liver and mouse hepatic cell line treated with thioacetamide (TAA) and identified several common genes. In this study, we selected genes to validate them as potential biomarkers for hepatotoxicity on the relevance of in vitro and in vivo system. Three up-regulated, aquaporin 8 (Aqp8), glutathione peroxidase 1 (Gpx1), succinate-CoA ligase, GDP-forming, alpha subunit (Suclg1) and two down-regulated, DnaJ (Hsp40) homolog subfamily C member 5 (Dnajc5) and tumor protein D52 (Tpd52) genes were tested for their effects in vitro. For characterization of gene function, short interfering RNA (siRNA) for each gene was synthesized and transfected in mouse hepatic cell line, BNL CL.2. Cell viability, mRNA expression level and morphological alterations were investigated. We confirmed siRNA transfection against selected five genes induced down-regulation of respective mRNA expression. siRNA transfection in general decreased cell viability in different degrees and induced morphological changes such as membrane thickening and alterations of intracellular structures. This suggests that these genes could be associated with TAA-induced toxicity. Furthermore, these genes may be used in the investigation of hepatotoxicity for better understanding of its mechanism.