Figure 3. Regulation of cell growth by ORP1S deletion mutants.

(A) CMY136 yeast (a ura3 his3 trp1 leu2 sec14-1^ts kes1::HIS3) were transformed with the pESC-URA vector containing ORP1S or the indicated ORP1S deletion mutants in-frame with an N-terminal Myc epitope tag and under the control of the galactose-inducible GAL1 promoter. Identical numbers of exponential-phase cells were harvested and washed, and serial dilutions were spotted on to minimal medium agar plates containing the appropriate nutrients required for strain growth and plasmid maintenance, with galactose as carbon source, and grown at 25 °C or 37 °C for 4 days. (B) Western blot analysis of the expression levels of Myc-tagged ORP1S mutants, with Pgk1p as a loading control. (C) Growth phenotypes for all ORP1S deletion constructs that were expressed in yeast strain CMY136. Results are representative of at least three separate experiments.