Figure 3.

Sec23–Sec31 interaction interfaces are dispensable for coat assembly. (A) Serial dilutions of sec31Δ and sec31Δ sed4Δ strains expressing the deletion and substitution mutants indicated were grown on 5-FOA, revealing no loss of fitness associated with the loss of any of these interfaces. (B) Serial dilutions of a sec31Δ strain expressing Nhis-Sec31 mutants as indicated were grown on 5-FOA, revealing lethality associated with the combination of the N-terminal His tag and loss of PPP motifs. (C) Recruitment of the coat to synthetic liposomes as described for Fig. 2 B revealed that each of the mutants indicated were recruited as well as WT. (D) In vitro budding from yeast microsomes with the proteins indicated revealed normal budding efficiency, except for the Nhis-tagged proteins, which were reduced in their ability to generate vesicles with GTP.