Model for sphingolipid metabolism and Svf1 co-localization with the IPC synthase. (a) Overview of the multi-pathway flux analysis. ¹³C₃¹⁵N-serine and ²H₆-inositol were added as tracers to exponentially growing cells. The potential incorporation into SP metabolites are shown in a simplified model of yeast SP metabolism. KDH, 3-ketodihydrosphingosine; DHS, dihydrosphingosine; PHS, phytosphingosine; PI, phosphatidylinositol; IPC, inositol phosphorylceramide; MIPC, mannosylinositol phosphorylceramide; M(IP)₂C, mannosyldiinositol phosphorylceramide as well as in phosphatidylinositol and phosphatidylserine. (b) Svf1-GFP (green) was expressed in cells expressing Mnn9-mKate (cis-Golgi, red) and Aur1-Halo (mid-Golgi, blue). Scale bar = 5 µM. (c) Qunatification of Svf1 dots co-localizing with Mnn9, Aur1, Mnn9, and Aur1, only Mnn9, and only Aur1. (n = 100 Svf1 dots, triplicates).