Arabidopsis acyl-CoA-binding proteins and their protein partners are candidates for plant biotechnology (invited talk)

Functional Genomics SessionAcyl-CoA-binding proteins (ACBPs) have been characterized from mammals, yeast, Drosophila and plants including the model plant, Arabidopsis thaliana. Six genes encode ACBPs in Arabidopsis and these ACBPs are distributed into four classes: (i) the small 10-kDa ACBP6, (ii) ACBP1 and ACBP2 with ankyrin repeats, (iii) ACBP4 and ACBP5 with kelch motifs and (iv) ACBP3 with the acyl-CoA-binding domain located at the C-terminus. We have demonstrated that recombinant ACBPs bind acyl-CoA esters and phospholipids. The subcellular localization of ACBPs to various compartments revealed that they are nonredundant proteins. Using transformed Arabidopsis overexpressing the various ACBPs and their corresponding acbp mutants, we showed that Arabidopsis ACBPs participate in abiotic and biotic stress responses. In particular, ACBP1 and ACBP2 are responsive to oxidative stress, ACBP2 to drought treatment, ACBP3 to Pseudomonas syringae infection, and ACBP6 to freezing treatment. As ankyrin repeats and kelch motifs are known to mediate protein-protein interactions, we have initiated attempts to identify the protein partners of Arabidopsis ACBPs. Our investigations and those of others have revealed that some of the proteins that interact with ACBPs, as identified in yeast two-hybrid analysis and/or bimolecular fluorescence complementation, are also stress- responsive proteins. These results suggest that ACBPs and their protein interactors represent promising candidates for applications in plant biotechnology