FIG. 1.
(A) Secretion of mature α-factor by cells producing Mfα1-Sec71p and Mfα1-Sec63p. Wild-type (WT) (SNY9), Δrer1 (SKY7), and rer2-2 (SNH23-7D) cells expressing Mfα1-Sec71p or Mfα1-Sec63p on a single-copy vector were examined by the halo assay at 23°C. (B) The rer2 mutants missecrete BiP. Wild-type (SNY9), rer2-2 (SNH23-16C), Δrer2 (SMY41), and Δsrt1 (SNY25) cells were grown in YPD medium at 23°C to the early logarithmic phase. Proteins from the medium (equivalent to 1.5 × 106 cells) were analyzed by immunoblotting with the anti-BiP antibody.