Abstract
To understand molecular mechanisms of endocytosis in plants, we have been focusing our attention on Rab5 GTPases. Arabidopsis thaliana has two different types of Rab5-related GTPases (conventional-type ARA7 and RHA1 and plant-unique-type ARA6). Activation of Rab5 members is mediated by guanine nucleotide exchange factors (GEF) which contain a highly conserved Vps9 domain. Arabidopsis genome appears to have two genes, VPS9a and VPS9b, encoding Rab5 GEF marked by the Vps9 domain (1). They show high similarity in the amino acid sequence, but exhibit different expression patterns. Comparison of biochemical properties and functions of two VPS9s will be presented. (1) Goh et al., Plant Cell, in press
