Abstract
The RAB GTPase, including RAB5, is known to act as a molecular switch through cycling between GTP-bound and GDP-bound states. The GTP-bound state is considered as the active form to which effector molecules specifically interact. In mammalian cells, RAB5 effectors are known to trigger various downstream phenomena. RAB5 is conserved in a broad range of eukaryotic organisms including plants. In addition to the conventional-type RAB5 homologs, land plants possess plant-specific RAB5 homologs (ARA6 in Arabidopsis thaliana) (Ueda et al., 2001). Our previous studies indicated that ARA6 and conventional-type RAB5 regulate plant-specific functions by coordinating different membrane traffic pathways. This regulatory system is thought to involve RAB5 effector molecules; however, the plant RAB5 effectors are hitherto unknown. To elucidate the molecular basis of such system, we focused on ARA6 and identified its effectors. In this meeting, the cell biological and physiological significance of PUF2 (Plant-unique RAB5 Effector 2)-ARA6 interaction will be discussed.
