Fig. 8.

Btn1p suppresses the Cpy1p secretion defect of vps34Δ cells. Ectopic expression of Btn1p rescues the Cpy1p secretion defect of vps34Δ cells but not that of vps26Δ or vps10Δ cells. (A) Colony blot assay of indicated cells grown on MM agar plates plus supplements for 6 hours. (B) Bar chart depicting mean density values relative to wild-type level of Cpy1p secretion of colony blot assays from indicated cells (mean of two experiments). (C-F) The rescue of the Cpy1p secretion defect of vps34Δ cells is specific to native Btn1p protein and to levels of protein expression: colony blot assay of indicated cells grown on MM agar plates plus supplements for 6 hours with native (Btn1p) or mutant Btn1p^G136A protein in the absence (C) or presence (D) of thiamine (to repress expression). Bar charts depicting mean density values relative to wild-type level of Cpy1p secretion of colony blot assays from indicated cells without (E) and with (F) thiamine-induced promoter repression (mean ± s.d. of four and two experiments, respectively). ^**P<0.01.