Fig. 5: Metabolomic analysis shows increased levels of proline in put6Δ yeast cells.

a A biochemical pathway depicting proline metabolism in S. cerevisiae. Proline catabolism occurs in mitochondria and is highlighted in bold letters. b–i LC-MS-based quantification of proline (b), glutamate (c), N-acetyl glutamate (d), ornithine (e), citrulline (f), arginine (g), α-ketoglutarate (h), and glutamine (i) in put6Δ yeast cells cultured in indicated nitrogen source (Pro—proline, Glu—glutamate). Data were normalized to WT and plotted as mean ± SD (n = 3 biologically independent experiments). j Time course of [¹⁴C] proline uptake in isolated mitochondria from ACY WT and put6Δ yeast cells grown in proline as the sole nitrogen source. All the data points were normalized to time zero and plotted as mean ± SD (n = 3 biologically independent experiments). k–m Time course of P5C efflux (k), glutamate accumulation (l), and glutamate efflux (m) in WT and put6Δ mitochondria following 1 mM proline addition. All the data points were normalized to time zero and plotted as mean ± SD (n = 3 biologically independent experiments). WT and mutants used in this panel are from prototrophic ACY genetic background (see Supplementary Table 1). Source data are provided as a Source data file.