Identification and functional expression in yeast of a prenylcysteine α-carboxyl methyltransferase gene from Arabidopsis thaliana

Most isoprenylated proteins are α-carboxyl-methylated. However, despite numerous studies linking protein isoprenylation in plants to cell cycle control, meristem development, and phytohormone signaling, α-carboxyl methylation of isoprenylated plant proteins has not been characterized in detail. Here, we report the cloning of a prenylcysteine α-carboxyl methyltransferase gene (AtSTE14) from Arabidopsis thaliana. AtSTE14 restores fertility and enzymatic activity to a ste14 mutant of Saccharomyces cerevisiae, confirming its identity as a bona fide prenylcysteine α-carboxyl methyltransferase gene. Furthermore, the presence of AtSTE14 transcripts in various Arabidopsis organs suggests a ubiquitous role for the AtSTE14 protein in plant growth and development. These results demonstrate that Arabidopsis thaliana possesses a functional prenylcysteine α-carboxyl methyltransferase involved in post-isoprenylation protein processing.