The Yeast Cell Fusion Protein Prm1p Requires Covalent Dimerization to Promote Membrane Fusion
Figure 3
Two cysteines are required for formation of functional covalent Prm1p dimers.
(A) Anti-GFP Western blot on whole cell lysate after expression of PRM1-GFP or cysteine-substituted mutants was induced with 10 µg/ml α-factor for 90 min. (B) prm1Δ MATα cells expressing cytoplasmic GFP and prm1Δ MATa cells bearing the indicated PRM1 alleles on low copy plasmids were mated on EGTA-containing plates at 30°C for 3 h. Mating pairs were fixed and mating pair fate was scored microscopically by observing diffusion of cytoplasm throughout the mating pair (fusion) or loss of GFP signal and abnormal morphology (lysis).