Host: The Japanese Society of Plant Physiologists
Pages 0336
Mammalian Rab5 GTPase is known to regulate not only endosomal fusion but also signaling through endosomes. Rab GTPases are activated by specific guanine-nucleotide exchange factors (GEFs), which accelerate the exchange of GDP for GTP. Vps9 domain, a catalytic core for activation of Rab5, is conserved in all Rab5 GEFs identified thus far. We have already demonstrated that the Arabidopsis VPS9a can activate all of three Arabidopsis Rab5 members (ARA6, ARA7, and RHA1). VPS9a comprises the conserved Vps9 domain at N-terminus and C-terminal region with no similarity to known domains. We found that truncation of the C-terminal region of VPS9a confers increased GEF activity toward ARA6. Detailed functional analysis of the C-terminal region of VPS9a is now underway.
