Abstract
RAB5 is conserved in a broad range of eukaryotic organisms including plants. In addition to the conventional type of RAB5 homologs, land plants conserve plant-specific RAB5 homologs with unique structure (ARA6 in Arabidopsis thaliana). Our previous studies provided a new insight that land plants have established an original and possibly more complex mechanism for endocytotic regulation using ARA6, which should be required for the plant-specific way of living. In order to elucidate the molecular basis of such system, ARA6 effectors were determined. We have identified seven putative plant-unique RAB5 effectors(PUFs), among which PUF3 exhibits very interesting behavior. PUF3 localizes on ARA6 positive endosomes, which is regulated by the nucleotide state of ARA6. We have also found that PUF3 binds preferentially to PI4P via PH domain. In this meeting, the cell biological and physiological significance of PUF3-ARA6 interaction will be discussed.
