Fig. 6: Uncoupling of the ISR from ER stress is a consequence of mycolactone’s effect on the Sec61 translocon, but is not a general feature of translocation inhibition. | Cell Death & Disease

Fig. 6: Uncoupling of the ISR from ER stress is a consequence of mycolactone’s effect on the Sec61 translocon, but is not a general feature of translocation inhibition.

From: Inhibition of Sec61-dependent translocation by mycolactone uncouples the integrated stress response from ER stress, driving cytotoxicity via translational activation of ATF4

Fig. 6

a, b An unbiased screen for mycolactone-resistant clones was performed in HCT-116 cells, yielding clones with heterozygous missense mutations in Sec61A1. Parental HCT-116 cells and representative clones with D60G and R66K were analysed. a Normalised viability index of cells treated with mycolactone for 5 days, assessed by MTT assay. b Immunoblot of lysates that were treated with DMSO, mycolactone or starved of Leucine (Leu−) for 24 h. c, d Wild-type MEFs were treated with CT8 (c) or CT9 (d) for the indicated times or tunicamycin (Tuni). Lysates were analysed by immunoblotting. e, f Wild-type (WT) or PERK−/− MEFs were treated as shown and the lysates were analysed by immunoblotting. g Wild-type MEFs were treated as shown. Total RNA was isolated and used as a template for RT-PCR of XBP-1 (upper panel) which was then digested with Pst1 and separated on a 2% agarose gel (lower panel). The migration of molecular weight markers in bp is indicated. S spliced, US unspliced. All data representative of at least two independent experiments. h HeLa cells were treated as shown for 10 h. Relative fold change (ΔΔCt) for steady-state mRNA levels (Mean ± SEM, n = 3 independent experiments). All immunoblots show the approximate migration of molecular weight markers in kDa

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