Figure 1.

TIF51A is required for respiration independently of hypusination. (a) Growth of the WT, tif51A-1, tif51A-3 and tif51B∆ strains was tested in YEP medium containing 2% glucose (YPD), 2% galactose (YPGal), 2% glycerol (YPGly) or 2% ethanol (YPEtOH) at the indicated temperatures. (b) The WT cells were grown in YPD, YPGal, YPGly or YPEtOH to the exponential phase (OD₆₀₀ of 0.5). Relative TIF51A and TIF51B mRNA levels were determined. (c) The WT, tif51A-1 and tif51A-3 strains were grown in YPGal at permissive temperature (25 °C) and transferred to non-permissive temperature (37 °C) for 4 h until an OD₆₀₀ of 1.5–2 was reached. Relative oxygen consumption rates are shown. (d) Western blotting of eIF5A in the WT, tif51A-1 and tif51A-3 cells at 25 °C and 37 °C showing eIF5A depletion. Glucose-6-phosphate dehydrogenase (G6PDH) protein levels were used as loading controls. tif51A-3 mutated protein migrates slightly more slowly than the wild-type Tif51A and tif51A-1 mutant due to the mutation of glycine 118 to aspartic. (e) The WT and lia1∆ strains were grown in YPGal at 30 °C until an OD₆₀₀ of 1.5–2 was reached. Relative oxygen consumption rates are shown. (f) Western blotting of hypusinated eIF5A in the WT and lia1∆ showing differences in hypusination. G6PDH protein levels were used as the loading controls. (b,c,e) The results are shown as the means ± SD of three independent experiments and expressed in relation to the value for the 2% glucose condition or the WT. Statistical significance was measured by a Student’s t-test in relation to the 2% glucose condition or WT. ** p < 0.01, *** p < 0.001.