%0 Journal Article
%T Saccharomyces cerevisiae FKBP12 binds Arabidopsis thaliana TOR and its expression in plants leads to rapamycin susceptibility
%A Rodnay Sormani
%A Lei Yao
%A Beno£¿t Menand
%A Najla Ennar
%A C¨¦cile Lecampion
%A Christian Meyer
%A Christophe Robaglia
%J BMC Plant Biology
%D 2007
%I BioMed Central
%R 10.1186/1471-2229-7-26
%X Here we show that none of the FKBPs from the model plant Arabidopsis (AtFKBPs) is able to form a ternary complex with the FRB domain of AtTOR in the presence of rapamycin in a two hybrid system. An antibody has been raised against the AtTOR protein and binding of recombinant yeast ScFKBP12 to native Arabidopsis TOR in the presence of rapamycin was demonstrated in pull-down experiments. Transgenic lines expressing ScFKBP12 were produced and were found to display a rapamycin-dependent reduction of the primary root growth and a lowered accumulation of high molecular weight polysomes.These results further strengthen the idea that plant resistance to rapamycin evolved as a consequence of mutations in plant FKBP proteins. The production of rapamycin-sensitive plants through the expression of the ScFKBP12 protein illustrates the conservation of the TOR pathway in eukaryotes. Since AtTOR null mutants were found to be embryo lethal [1], transgenic ScFKBP12 plants will provide an useful tool for the post-embryonic study of plant TOR functions. This work also establish for the first time a link between TOR activity and translation in plant cellsThe TOR (Target Of Rapamycin) pathway is a conserved eukaryotic pathway regulating growth, cell integrity and survival as a function of many different inputs including nutrient availability, energy status and mitogens in multicellular organisms [2-4]. TOR is a very large protein with a Ser/Thr kinase domain preceded by several HEAT repeats which interact with the numerous TOR protein partners. Studies in yeast and animal cells have shown that TOR acts positively on the activity of the eIF4F translation initiation complex and on the transcription of ribosomal RNA and protein genes therefore promoting growth in nutrient sufficient conditions [5-7]. In starvation conditions TOR regulates the utilization of alternative energy resources, allows autophagy and generally drive the cell towards survival pathways [8-12]. Rapamycin, an antibiotic
%U http://www.biomedcentral.com/1471-2229/7/26