Paradoxical Sensitivity to an Integrated Stress Response Blocking Mutation in Vanishing White Matter Cells

• DOI: 10.1371/journal.pone.0166278
• Publication Date: 2016-11-03T17:53:33Z
• Authors: Yusuke Sekine; Alisa Zyryanova; Ana Crespillo-Casado; Niko Amin-Wetzel; Heather P. Harding; David Ron
• Keywords: Integrated stress response; eIF2; Eukaryotic translation

The eukaryotic translation initiation factor eIF2B promotes mRNA as a guanine nucleotide exchange (GEF) for 2 (eIF2). Endoplasmic reticulum (ER) stress-mediated activation of the kinase PERK and resultant phosphorylation eIF2's alpha subunit (eIF2α) attenuates GEF activity thereby inducing an integrated stress response (ISR) that defends against protein misfolding in ER. Mutations all five subunits human cause inherited leukoencephalopathy with vanishing white matter (VWM), but role ISR its pathogenesis remains unclear. Using CRISPR-Cas9 genome editing we introduced most severe known VWM mutation, EIF2B4A391D, into CHO cells. Compared to isogenic wildtype cells, cells mutation was impaired mutant experienced modest enhancement ISR. However, despite their enhanced ISR, imposed by intrinsic defect eIF2B, disrupting inhibitory effect phosphorylated eIF2α on contravening EIF2S1/eIF2αS51A functions upstream selectively enfeebled both EIF2B4A391D related EIF2B4R483W basis paradoxical dependence mutations intact genotype unclear, rates survival from stressors normally activate were not reproducibly affected mutations. Nonetheless, our findings support additional layer complexity development VWM, beyond hyperactive