Functional characterization of the Arabidopsis thaliana orthologue of Tsc13p, the enoyl reductase of the yeast microsomal fatty acid elongating system.

The protein encoded by the Arabidopsis At3g55360 gene was selected as a candidate for the enoyl reductase of the microsomal elongase system based on its homology to the Tsc13p protein of S. cerevisiae. The studies presented here demonstrate that heterologous expression of At3g55360 functionally complements the temperature-sensitive phenotype of a yeast tsc13 mutant that is deficient in enoyl reductase activity. Furthermore, AtTSC13 is shown to interact physically with the Elo2p and Elo3p components of the yeast elongase complex. At3g55360 apparently encodes the sole enoyl reductase activity associated with microsomal fatty acid elongation in Arabidopsis. Consistent with this conclusion, AtTSC13 is ubiquitously expressed in Arabidopsis.