CUE domain found in ancient ubiquitous protein 1 (AUP1), autocrine motility factor receptor (AMFR) and similar proteins
AUP1 is a component of the HRD1-SEL1L endoplasmic reticulum (ER) quality control complex and is essential for US11-mediated dislocation of class I MHC heavy chains. AMFR is an internalizing cell surface glycoprotein that is localized in both plasma membrane caveolae and the ER, and involves in the regulation of cellular adhesion, proliferation, motility and apoptosis, as well as in the process of learning and memory. Cue1p is an N-terminally membrane-anchored endoplasmic reticulum (ER) protein essential for the activity of the two major yeast RING finger ubiquitin ligases (E3s) implicated in ER-associated degradation (ERAD). This family also includes plant E3 ubiquitin protein ligases RIN2, RIN3, and similar proteins. Comparing with other CUE domain-containing proteins, some family members from higher eukaryotes do not bind monoubiquitin efficiently, since they carry LP, rather than FP among CUE domains.