The Diversity of Ubiquitin Recognition: Hot Spots and Varied Specificity

Ubiquitin is attached to a large number of proteins and gives rise to signaling events that modulate many cellular functions. These signals are often based on the recognition of polyubiquitin chains, which are produced in a variety of lengths and linkage patterns. In addition, proteins that are similar to ubiquitin in structure and function are often recognized by an overlapping set of partners. Research over the past several years has expanded our understanding of how ubiquitin and ubiquitin-like proteins are recognized. Most interactions occur at a few distinct surface areas; however, individual binding partners have specific, unique contacts that impart specificity. In this review, we summarize available information to facilitate comparisons across the ubiquitin-like family.