title: Decoding the SUMO signal.
abstract: SUMO (small ubiquitin-like modifier) emerged from the shadow of the well-established ubiquitin some 15 years ago when it was shown that a distinct conjugation pathway was responsible for SUMO modification. Since then it has been established that SUMO modifies over a thousand substrates and plays diverse roles in many important biological processes. Recognition of SUMO is mediated by short peptide sequences known as SIMs (SUMO-interaction motifs) that allow effector proteins to engage SUMO-modified substrates. Like ubiquitin, SUMO can form polymeric chains, and these chains can be recognized by proteins containing multiple SIMs. One protein that contains such a sequence of SIMs also contains a RING (really interesting new gene) domain that is the hallmark of a ubiquitin E3 ligase. This ubiquitin ligase known as RNF4 (RING finger protein 4) has the unique property that it can recognize SUMO-modified proteins and target them for ubiquitin-mediated proteolysis. Structural and biochemical analyses of RNF4 has shed light on the long sought after mechanism of ubiquitin transfer and illustrates how its RING domain primes the ubiquitin-loaded E2 for catalysis.
authors.affiliation: Wellcome Trust Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, U.K. r.t.hay@dundee.ac.uk
authors.forename: Ronald T
authors.initials: RT
authors.lastname: Hay
mesh_terms: D000818:Animals; D004249:DNA Damage; D006801:Humans; D015398:Signal Transduction; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*; D013379:Substrate Specificity; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: D025841:Small Ubiquitin-Related Modifier Proteins; D025801:Ubiquitin; D044767:Ubiquitin-Protein Ligases