Figure 4.

Relocalization of the mutant desaturase is lipid dependent and results in the synthesis of more saturated lipids. (A) Relocalization of the mutant desaturase in cells cultivated with either saturated (sfa) or unsaturated (ufa) fatty acids. Cells expressing Ole1^tsp-GFP (YRS1314) were cultivated in the presence of fatty acids at 30°C for 2 h before a shift to 37°C for 30 min. Bar, 5 μm. (B) Incorporation of [¹⁴C]palmitic acid into the phospholipid fraction of ole1^ts mutant cells. Cells were pulse-labeled with [¹⁴C]palmitic acid at 37°C for 15 min, and incorporation of radiolabeled fatty acids into newly synthesized phospholipids was determined by radio-GC analysis. A comparison of the relative content of saturated (sfa) and unsaturated (ufa) fatty acids in newly synthesized lipids of wild-type and desaturase mutant cells is shown in the table inset.