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

Most isoprenylated proteins are alpha -carboxyl-methylated. However, despit e numerous studies linking protein isoprenylation in plants to cell cycle c ontrol, meristem development, and phytohormone signaling, alpha -carboxyl m ethylation of isoprenylated plant proteins has not been characterized in de tail. Here, we report the cloning of a prenylcysteine alpha -carboxyl methy ltransferase gene (AtSTE14) from Arabidopsis thaliana. AtSTE14 restores fer tility and enzymatic activity to a ste14 mutant of Saccharomyces cerevisiae , confirming its identity as a bona fide prenylcysteine alpha -carboxyl met hyltransferase gene. Furthermore, the presence of AtSTE14 transcripts in va rious Arabidopsis organs suggests a ubiquitous role for the AtSTE14 protein in plant growth and development. These results demonstrate that Arabidopsi s thaliana possesses a functional prenylcysteine alpha -carboxyl methyltran sferase involved in post-isoprenylation protein processing.