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In this study, we investigated the protective effect of glutamine on barrier dysfunction induced by ethanol, by using human epithelial colorectal adenocarcinoma cells (Caco-2). Our results show that addition of glutamine to culture medium significantly improved the disruption of integrity caused by ethanol, which was associated with increased expression of heat shock protein 70 (Hsp70). Ethanol exposure moderately activates heat shock factor 1 (HSF1), which was characterized by increased DNA-binding activity and phosphorylation status of HSF1. Remarkably, glutamine treatment enhanced ethanol-mediated expression of Hsp70 and activation of HSF1. Up-regulation of Hsp70 by pretreatment with heat stress also promoted recovery from the ethanol-induced barrier dysfunction. Taken together, these observations indicate that glutamine protects the intestinal barrier function in Caco-2 cells, in part by modulating HSF1-mediated Hsp70 expression. [ABSTRACT FROM AUTHOR]

In this study, we investigated the protective effect of gluta-mine on barrier dysfunction induced by ethanol, by using human epithelial colorectal adenocarcinoma cells (Caco-2). Our results show that addition of glutamine to culture me-dium significantly improved the disruption of integrity caused by ethanol, which was associated with increased ex-pression of heat shock protein 70 (Hsp70). Ethanol exposure moderately activates heat shock factor 1 (HSF1), which was characterized by increased DNA-binding activity and phos-phorylation status of HSF1. Remarkably, glutamine treat-ment enhanced ethanol-mediated expression of Hsp70 and activation of HSF1. Up-regulation of Hsp70 by pretreatment with heat stress also promoted recovery from the ethanol-induced barrier dysfunction. Taken together, these observations indicate that glutamine protects the intestinal barrier function in Caco-2 cells, in part by modulating HSF1-mediated Hsp70 expression. [ABSTRACT FROM AUTHOR]

Here, we produced the C-terminal truncation variants of mouse inducible heat shock protein 72 (Hsp72) to elucidate the regulatory role of the C-terminal helical lid of Hsp70 for substrate recognition. All of the truncation variants containing the substrate binding domain bound a short-length peptide substrate CLLLSAPRR. When a large mass reduced carboxymethyl α-lactalbumin (RCMLA) as a substrate was used in gel filtration experiment, we observed the complex formation only for the truncation variants containing the long α-helix C in the helical lid. However, RCMLA binding occurred even for the variants lacking α-helix C when their C-terminal region was anchored onto a solid phase. Together with the finding that helix C is involved in the self-association of Hsp70, our present data suggest that the C-terminal region of Hsp70 modulates the substrate recognition and its kinetics may be substrate-mass dependent. [Copyright &y& Elsevier]