FIGURE 1.

Dnf1 variants differ in their suppression of drs2Δ PS asymmetry defects and cold-sensitive growth. A–C, a drs2Δ strain harboring either an empty vector or a vector expressing the indicated Drs2 or Dnf1 variant, were grown for 20 h at 30 °C with increasing concentrations of papuamide B (A and C) or duramycin (B). Among Dnf1 variants competent for NBD-PS transport, Dnf1 N550S is uniquely capable of restoring plasma membrane asymmetry in drs2Δ better than WT Dnf1 for PS asymmetry (A) but not PE asymmetry (B). C, overexpressing WT Dnf1 or Dnf1[Y618F] provides minor suppression of the PS asymmetry defect. D, growth of drs2Δ harboring the indicated Drs2 or Dnf1 variants at 30 °C or 20 °C. Dnf1 N550S suppresses drs2Δ cold-sensitive growth better than WT Dnf1 or other Dnf1 NBD-PS-transporting alleles.