Fig. 2.

Requirement of the Rab GTPase Ypt31p and TRAPPII components in Sec14p function. (A) The isogenic sec14^ts yeast strains indicated were grown to logarithmic phase, 10-fold serial dilutions were spotted on YEPD agar plates, and cells were incubated for 48–72 h at 25, 37, or 39°C. (B and C) The secretion index was determined by comparing the activity of extracellular invertase to total invertase. Data are the mean of at least three independent experiments ± SE. (D) Diploid SEC14/sec14^ts TRS130/trs130^ts cells were grown in culture at 25°C. Identical cell numbers were serial diluted, plated, and grown at 25 or 37°C. Growth of five different SEC14/sec14^ts TRS130/trs130^ts strains is shown. A SEC14/sec14^ts TRS130/trs130^ts diploid strain was transformed with a low-copy plasmid carrying the SEC14 gene, or empty vector, grown in culture to logarithmic phase at 25°C; identical cell numbers were serial diluted; and growth at 30 and 37°C was determined.