CUE domain found in vacuolar protein sorting-associated protein 9 (VPS9) and similar proteins
VPS9, also called vacuolar protein-targeting protein 9, is a cytosolic yeast protein required for localization of vacuolar proteins, such as the soluble vacuolar hydrolases CPY and PrA. It may bind and act as an effector of a rab GTPase and plays a role in vacuolar protein sorting (VPS) pathway. VPS9 contains a region called GBH domain that is related to mammalian Ras-binding proteins, Rin1 and JC265, and may negatively regulate Ras-mediated signaling in yeast Saccharomyces cerevisiae. This model corresponds to the N-terminal CUE domain that interacts specifically with monoubiquitin and regulates intramolecular monoubiquitylation.