InterPro domain: IPR019452

This entry represents a domain found in the vacuolar sorting protein Vps39 and transforming growth factor beta receptor-associated protein Trap1. Vps39, a component of the C-Vps complex, is thought to be required for the fusion of endosomes and other types of transport intermediates with the vacuole [ 1 , 2 ]. In Saccharomyces cerevisiae (Baker's yeast), Vps39 has been shown to stimulate nucleotide exchange [ 3 ]. Trap1 plays a role in the TGF-beta/activin signaling pathway. It associates with inactive heteromeric TGF-beta and activin receptor complexes, mainly through the type II receptor, and is released upon activation of signaling [ 4 , 5 ]. The precise function of this domain has not been characterised.

1. Vam2/Vps41p and Vam6/Vps39p are components of a protein complex on the vacuolar membranes and involved in the vacuolar assembly in the yeast Saccharomyces cerevisiae. J. Biol. Chem. 272, 11344-9
2. Morphological classification of the yeast vacuolar protein sorting mutants: evidence for a prevacuolar compartment in class E vps mutants. Mol. Biol. Cell 3, 1389-402
3. New component of the vacuolar class C-Vps complex couples nucleotide exchange on the Ypt7 GTPase to SNARE-dependent docking and fusion. J. Cell Biol. 151, 551-62
4. A novel protein distinguishes between quiescent and activated forms of the type I transforming growth factor beta receptor. J. Biol. Chem. 273, 9365-8
5. Transforming growth factor-beta receptor-associated protein 1 is a Smad4 chaperone. J. Biol. Chem. 276, 19495-502