Figure 5.
Irc21 Exerts PP2A-Dependent and PP2A-Activating Metabolic Regulations
(A) Unsupervised hierarchical clustering of irc21Δ and rrd1Δ mutants (six replicates each) based on metabolome alterations during logarithmic growth in rich medium.
(B) Summary of metabolome alterations of irc21Δ and rrd1Δ mutants during logarithmic growth in rich medium. Left: scatterplot of quantitative alterations of individual metabolites in irc21Δ and rrd1Δ mutants compared with a congenic WT identifies irc21Δ-specific (blue), rrd1Δ-specific (yellow), common (green, PP2A signature), and opposite (red) regulations. Right: Venn diagram representation of the intersection of metabolic alterations in irc21Δ and rrd1Δ mutants and intersection significance p value determined by chi-square test.
(C) Heatmap representation of altered metabolites by signature. Top: PP2A signature (common alterations in irc21Δ and rrd1Δ). Bottom: specific regulations in irc21Δ and opposite regulations in irc21Δ and rrd1Δ. As indicated, metabolites were grouped by class.
(D) 3-keto-sphinganine, sphinganine, sphinganine-1p, and dihydroceramide were quantified in WT and irc21Δ cells. Average values are shown, and error bars represent SEM.
(E) Simplified scheme representing ceramide biosynthesis in S. cerevisiae. Colored metabolites indicate an increase (red) or a decrease (green) of their amount in irc21Δ cells.
(F) WT and irc21Δ cells were grown on YPD plates with or without myriocin.
(G) WT and irc21Δ cells were grown on YPD plates with or without syringomycin E.
(H) WT and irc21Δ cells were grown in SD medium with or without Fumonisin B1.
(I) Cells were grown on YPD + HU with or without ceramide.
(J) Cells were arrested in G1 with α-factor and released in YPD with or without 0.2 M HU, 15 μM ceramide, or 0.2 M HU in combination with 15 μM ceramide for 3 hr.
See also Figure S5.