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

Most isoprenylated proteins are alpha -carboxyl-methylated. However, despite numerous studies linking protein isoprenylation in plants to cell cycle control, meristem development, and phytohormone signaling, alpha -carboxyl methylation of isoprenylated plant proteins has not been characterized in detail. Here, we report the cloning of a prenylcysteine alpha -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 alpha -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 alpha -carboxyl methyltransferase involved in post-isoprenylation protein processing.