Fig. 4: Regulation of GRP78 and MC4R in the hypothalamus under ER stress. | Experimental & Molecular Medicine

Fig. 4: Regulation of GRP78 and MC4R in the hypothalamus under ER stress.

From: Glucose-regulated protein 78 binds to and regulates the melanocortin-4 receptor

Fig. 4

Mice were exposed to an ER stressor, and their brains were removed. Hypothalamic protein extracts were subjected to western blotting and coimmunoprecipitation. For acute ER stress conditions, 10-week-old male mice were injected with tunicamycin (TM) or vehicle (DMSO) into the lateral ventricle (i.c.v., TM 80 µg/3.2 µl, twice every 6 h) and were killed 12 h after the first injection. For chronic ER stress conditions, 10–14-week-old male mice were fed a high-fat diet (HFD, 58.0% fat) or a normal diet (ND) for 20 weeks. The expression levels of ER stress marker proteins (pIRE1α, peIF2α, and XBP1s), GRP78, and MC4R in mice subjected to a acute ER stress (vehicle DMSO versus TM) or c chronic ER stress (ND versus HFD) were measured using western blotting. The interaction between GRP78 and MC4R was measured using coimmunoprecipitation under b acute ER stress or d chronic ER stress conditions. One-tailed Student’s t test for ad: TM, n = 3–9 per group; HFD, n = 5–7 per group, *P < 0.05, **P < 0.01 versus vehicle DMSO or ND group. The data are presented as the mean ± SEM

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