Extended Data Figure 8: C18:0 removal does not affect iron uptake or delivery.
From: Regulation of mitochondrial morphology and function by stearoylation of TFR1
a, HeLa cells cannot grow in the presence of deferoxamine (DFO), an iron chelator (top) whereas they grow in delipidated serum lacking C18:0 at a comparable rate to cells in control medium (bottom). n = 3. b, Treatment of HeLa cells with medium containing delipidated serum (lacking C18:0) for 24 h does not lead to transcriptional activation of iron deficiency response genes (bottom), which are activated by DFO-mediated iron chelation (24 h) as a positive control (top). n = 3. c, Treatment of HeLa cells with medium containing delipidated serum for 24 h or 4 days does not lead to a drop in levels of succinate dehydrogenase b (SDHB), which contains an Fe–S cluster. See Supplementary Fig. 19 for image of the uncropped full western blot. d–f, Treatment of HeLa cells with medium containing delipidated serum for 24 h or 4 days does not lead to a drop in activities of enzymes containing lipoylated subunits (PDH and OGDH) (d, e) or Fe–S-cluster-containing subunits (SDH) (f). DFO treatment to chelate iron from the medium, or siRNA-mediated depletion of the enzymes were used as positive controls (d–f, bottom). n = 4. g, Treatment of HeLa cells with medium containing delipidated serum (24 h) does not cause a reduction in transferrin uptake. Cells were treated with 25 μg ml−1 Alexa-488-coupled transferrin for 30 min. Representative images (left) and quantification of the amount of transferrin per cell (right) (n = 5). h, Treatment of HeLa cells with medium containing delipidated serum (24 h) does not reduce association of transferrin-containing vesicles with mitochondria. Crude mitochondria were fractionated from cells growing in medium containing or lacking C18:0, and the amount of transferrin that copurifies with mitochondria was analysed and quantified by immunoblotting. See Supplementary Fig. 19 for image of the uncropped full western blot. a, b, d–g, *P < 0.05, ***P < 0.001, ****P < 0.0001, not significant (NS) P ≥ 0.05, two-tailed t-test. Error bars show s.d.
