Fig. 7: Irp2 deficiency impairs Fe–S cluster protein function and causes ER stress.
From: Irp2 regulates insulin production through iron-mediated Cdkal1-catalyzed tRNA modification
a CRISPR/Cas9 depletion of Irp2 in INS-1 832/13 cells (sgIrp2.1, sgIrp2.2) and control parental cells grown in the presence of FAC (10 µg/ml), DFO (50 µM), or no treatment (NT) for 18 h. Irp2, Fth1, Ftl1 and TfR1 were assessed by western blot analysis to show efficacy of Irp2 knockdown and appropriate iron regulation. β-Actin is a loading control. Asterisk, nonspecific band. b The total iron content measured by ICP-MS and normalized to total cellular protein (n = 3 independent biological experiments). c, d Mitochondrial (c) and cytosolic (d) aconitase activity in control, sgIrp2.1, and sgIrp2.2 INS-1 cells grown in medium with or without supplemental FAC and normalized to total cellular protein. e, f Complex I activity (e) and complex IV activity (f) in lysates from control EV and shIrp2 cells grown in medium with or without supplemental FAC and normalized to total cellular protein (n ≥ 3 independent biological experiments). g ATP production in control INS-1, sgIrp2.1, and sgIrp2.2 cells grown in medium with or without supplemental FAC and assayed under basal (5 mM) glucose and after stimulation with 15 mM glucose for 1 h. ATP production was normalized to total cellular protein (n = 5 independent biological experiments). h Western blot analysis of eIF2α-P, eIF2α-total, and Grp78/BiP levels in sgIrp2.1 and sgIrp2.2 cells under basal glucose (5 mM) and after stimulation with 15 mM glucose. β-Actin is a loading control. Data are expressed as means ± s.e.m., unpaired two-tailed Student’s t test for b and f and one-way ANOVA with Tukey’s multiple comparisons test for c–e and g, *p < 0.05; **p < 0.01, ***p < 0.001. Source data are provided as a Source Data file.
