Figure 6.—

Growth assays of prk1Δ and sac6Δ mutants that express different Abp1p SH3 domain derivatives, a mutant version of Ark1p that lacks the Abp1p SH3 domain-binding region, or a mutant version of Scp1p that has a defective Abp1p SH3 domain-binding region. Serial dilutions of log-phase cultures of yeast strains expressing wild-type Abp1p, Abp1p bearing a Y54 SH3 domain substitution (SH3 Y54), Abp1p lacking an SH3 domain (ΔSH3), Ark1p lacking an Abp1p SH3 domain-binding polyproline region (ΔPP), or Scp1p bearing a PxxP substitution in its Abp1 SH3 domain-binding polyproline region (PP*) in the genetic background of prk1Δ (A) or sac6Δ (B) were spotted on media with or without caffeine and incubated for 3 days at 37° (prk1Δ) or 30° (sac6Δ). abp1, ark1, and scp1 alleles were integrated at the corresponding endogenous loci in all mutant backgrounds.