Fig. 2.

Atg32 required for SAM and spermidine production during heat stress. (A-B) GC-TOF-MS metabolomics results depicting average change of metabolites exhibiting significant differences between wild-type (WT) and atg32Δ yeast grown in YPGE medium at 30°C (A) or 37°C (B) (n=5). (C) Spermidine biosynthesis metabolic pathway. In this polyamine biosynthesis pathway, arginine is converted into the polyamine ornithine, which is the precursor to putrescine. Separately, methionine is the metabolic precursor for S-adenosyl methionine (SAM), which becomes de-carboxylated to form dcSAM. Putrescine and dcSAM converge to create spermidine. (D) Steady state levels of spermidine and spermidine precursors from extracts of wild-type and atg32Δ yeast grown at 30°C and 37°C in YPGE medium. Metabolite peak heights were determined by GC-TOF-MS and normalized using the mTIC (sum of peak heights of known metabolites) (n=5). (E) Relative SAM levels between wild-type and atg32Δ yeast grown in fermentative YPD medium and respiratory YPGE medium at 30°C and 37°C (n=3). (A-E). P-values determined using a unpaired two-tailed Student's t-test. A.U., arbitrary units; N.S., not significant. The center line denotes the median value (50th percentile), while the box contains the 25th to 75th percentiles of the dataset. The black whiskers with a dot at the end of a line mark the 5th and 95th percentiles, and values beyond these upper and lower bounds are considered outliers, marked with black dots.