Fig 2: ER stress and UPR response upon Q depletion Transmission electron microscopy images showing the increase in cystic ER vacuole upon q depletion. Arrowheads indicate rough endoplasmic reticulum while expansions are indicated by asterisks. Scale bar 250 nm.Representative images showing immunofluorescence of HeLa cells grown in S and SF medium in the absence or presence of q. Anti‐KDEL (ER stress marker), anti‐eIF2‐pS51 (ER stress‐induced inhibitor of translation), anti‐ATF4 (transcription factor that activates ER stress‐responsive genes), and anti‐Hps70 (chaperone). Nuclei were stained with Hoechst. Scale bar 10 μm.Data information: S (standard medium), SF (serum‐free medium), and q (queuine).

Fig 3: Molecular functions affected by Q Log2 fold changes in transcripts abundance and footprints at the indicated cell culture conditions. Pearson correlation coefficient (r) between footprints and mRNA abundance changes is shown.Volcano plot showing differentially translated mRNAs against adjusted P‐values for SF compared with SF + qR. Red dots indicate P adj < 0.1.Venn diagram showing the correlation of mRNA with high and low ribosome occupancy between the two rescue experiments (SF compared to SF + q and SF compared with SF + qR).Ingenuity molecular function analysis of differentially translated mRNAs. The top eight categories according to the ingenuity causal network P‐value are shown.Transmission electron microscopy images showing cellular overview with increased cystic vacuoles of the ER upon Q depletion. Arrowheads point to rough endoplasmic reticulum while expansions are indicated by asterisk. N, nucleus. Scale bar 500 nm. Automated quantification of the size of all vacuoles is presented in violin plot between the indicated grown conditions (5 optical fields). Black lines show the medians; white lines represent individual data points; polygons represent the estimated density of the data; *P < 0.05 (t‐test).Automated quantification of fluorescence intensity (AU: arbitrary units) relative to the immunofluorescence in Fig 6B. Error bars: ± SD (all cells in n ≥ 3 optical fields); *P < 0.05 (t‐test).Western blot showing increased eIF2α phosphorylation upon Q depletion. Actin and global eIF2 levels are used as loading controls. Quantification of the eIF2α phosphorylation signal normalized to β‐actin. Each bar represents three independent biological replicates. Error bars: ± SD; *P < 0.05 (t‐test).Data information: S (standard medium), SF (serum‐free medium), and q (queuine).Source data are available online for this figure.