FIG 6.

The C. neoformans arrestin mutant phenotypes. Serial dilutions of the WT strain, each individual arrestin mutant, and three independent arrestin null mutants were incubated on YPD medium with the following growth conditions/additives: 30°C, 39°C, caffeine (1 mg/ml), SDS (0.03%), high salt (1.5 M NaCl), and alkaline pH (pH 8). Cells were monitored visually for growth. The ali1Δ mutant exhibits modest susceptibility to caffeine. This phenotype is shared by, but markedly enhanced in, the ali2Δ mutant. The ali2Δ mutant also displays sensitivity to high salt. The ali3Δ mutant has modest growth defects at 39°C, as well as resistance to SDS. The ali4Δ mutant shares this SDS resistance phenotype, although it is enhanced compared to the ali3Δ mutant. The arrestin null mutants display reduced growth in the presence of 39°C, caffeine, and salt but enhanced growth in the presence of SDS and alkaline pH.