Cdc42p localizes to flat interfaces. (A) Model of curvature in shmoos, WT prezygotes, or curved prezygotes. (B and C) Deletion of FPS1 in one mating partner causes a curved ZCF. (B) Representative images of FM4-64-stained prezygoes. GFP–CDC42 (MY15747) and GFP–CDC42 fps1Δ (MY15864) cells were mated against either a fus1Δfus2Δ (JY429) or fus1Δfus2Δfps1Δ strain (MY15877) for 2.5 h at 30°, resuspended in TAF buffer, stained with FM4-64, and imaged. (C) Quantification of the radius of curvature in fps1Δ strains. The radius of the largest circle whose chord matches the contour of the ZCF of the GFP-positive cell was measured and averaged across all cells imaged. n ≥ 56 prezygotes per strain, from two or more experiments. Error bars denote the SEM. (D–F) Cdc42p is mislocalized in mating partners with a positively curved ZCF. (D) Representative images of prezygotes. The same matings were performed as in B for 2.5 h at 30°, fixed with 2% formaldehyde, and imaged. (E and F) Quantification of Cdc42p ZCF localization. Crosses are listed as MATa x MATα. n ≥ 89 prezygotes per strain. (G) Positively curved ZCFs do not alter Fus2p localization. GFP–CDC42 (MY15747) and GFP–CDC42 fps1Δ (MY15864) cells were transformed with FUS2–mCherry104 (pMR5821), mated against either a fus1Δfus2Δ (JY429) or fus1Δfus2Δfps1Δ strain (MY15877) for 2.5 h at 30°, fixed with 2% formaldehyde, and imaged. Bars, 2 µm.
