Analysis of enzymatic activity of AtCPT1 in the S. cerevisiae CPT mutants, rer2Δ or srt1Δ. (A) Expression of AtCPT1 in rer2Δ mutant complements defects in growth. rer2Δ cells were transformed with the empty plasmid pYES-DEST52 and AtCPT1 construct, respectively. Serially diluted yeast cultures were plated on solid YP-2% galactose medium and cultured for five days at 23 or 37 °C. (B) AtCPT1 expression in rer2Δ yeast strain restores glycosylation status of carboxypeptidase Y (CPY). Protein extracts from yeast transformants were separated by SDS-PAGE and analyzed by Western blot with anti-CPY antibody. The positions of mature CPY (mCPY) and hypoglycosylated glycoforms lacking between one and four N-linked glycans (−1 to −4) are indicated. (C) Polyisoprenoid profiles of rer2Δ or srt1Δ yeast mutants transformed with empty plasmid, AtCPT1, AtCPT1/Lew1 and Lew1, respectively. Presented are representative HPLC/UV chromatograms.