FIG 7.
Plasma membrane PI(4,5)P2 is not substantially affected by a decrease in PI(4)P. (A) Strains expressing the PI(4,5)P2 reporter GFP-PHPlcδ-PHPlcδ-GFP (wild type, PY1206; efr3Δ/Δ, PY3935; ypp1Δ/Δ, PY3958; stt4Δ/Δ, PY555) were imaged, and central z-sections of representative cells are shown with an inverted LUT. Bar, 5 μm. (B and C) Quantitation of plasma membrane and internal signals reveals that plasma membrane PI(4,5)P2 is largely unaffected in the absence of Efr3, Ypp1, and Stt4. The ratio of plasma membrane to internal signal and the relative plasma membrane signal were determined as for Fig. 5B and C (15 to 20 cells; 2 experiments for the wild type [WT]). For the wild type, the mean ratio of plasma membrane to internal signal was 2.8 and the ratio of plasma membrane to total signal was 0.7. *, P < 0.02; **, P < 0.01; ***, P < 0.0005.