This entry represents yeast Vta1 and its homologues from animals and plants. Vta1 interacts with the AAA ATPase Vps4 and is required for multivesicular body (MVB) sorting [, ]. This entry also includes LIP5 from Arabidopsis. LIP5 is a positive regulator of the Suppressor of K(+) Transport Growth Defect1 (SKD1) AAA ATPase in MVB biogenesis. It is also a target of pathogen-responsive mitogen-activated protein kinases (MPKs) and plays a critical role in plant basal resistance [, ]. Mammalian Vta1 homologue functions in MVB sorting and is required for HIV release [].
This domain can be found in the N terminus of the Vta1 protein, which is a class E vacuolar protein sorting (VPS) protein required for the formation of the multivesicular body (MVB) []. Proteins containing this domain also include Vta1 homologues, such as SBP1 from humans and LIP5 from Arabidopsis thaliana []. This domain can also be found in plant callose synthase, which is involved in callose synthesis at the forming cell plate during cytokinesis [].
This superfamily represents the N-terminal domain of vacuolar protein sorting-associated proteins and callose synthases. This domain contains seven alpha helices arranged into two antiparallel three-helix bundle modules. It has been proposed that vacuolar protein sorting-associated protein Vta1 interacts with Vps60 and Vps46/Did2 via this N-terminal domain [].
This is the C-terminal domain of the Vta1, which is a multivesicular body (MVB) protein. This domain promotes the ATP-dependent double ring assembly of Vps4. Furthermore, it has been shown that it is necessary and sufficient for protein dimerization. Mutations in Lys-299 and Lys-302 completely abolished the ability of Vta1 to stimulate the ATPase activity of Vps4 while mutation in Lys-322 had no effect [].
