The UMI motif mediates interaction with ubiquitin with a preference for 'Lys-63'-linked ubiquitin(1). The specificity for different types of ubiquitin is mediated by juxtaposition of ubiquitin-binding motifs (MIU and UMI motifs) with LR motifs.

1. Pinato S., Gatti M., Scandiuzzi C., Confalonieri S., Penengo L (2011). UMI, a novel RNF168 ubiquitin binding domain involved in the DNA damage signaling pathway. Mol. Cell. Biol., 31:118-126. PMID:21041483