The Ubiquitin-interacting Motif (UIM) is an alpha-helical Ubiquitin-binding domain found in many proteins that recognizes and traffics ubiquitinated cargo (1, 2). Ataxin-3, a deubiquitinating enzyme that contains three consecutive UIM motifs (amino acids (aa) 224-243, 244-263, 331-348), functions as a mixed lineage, chain editing enzyme that recognizes and binds K48-linked and K63-linked poly-Ubiquitin chains (3-5). The UIM domain of Ataxin-3 (aa 224-348) preferentially interacts with four or more Ubiquitin units of K48-linked or K63-linked poly-Ubiquitin chains or ubiquitinated substrates that contain these linkages (4, 6, 7).
This protein can be used for the isolation and identification of K48-linked (preferentially) or K63-linked poly-Ubiquitin chains or ubiquitinated substrates containing these linkages.
