SUMO-interacting motifs (SIMs) play a central role in the fate of SUMO-modified proteins. Here we report a real-time SUMO-binding assay. It can be applied to the identification of SIMs and to screening for the identification of novel SUMO-binding proteins. Using this assay, we investigated the SIMs in SETDB1 and MCAF1 to gain insight into the assembly of SETDB1-MCAF1-mediated gene silencing.

XopD (Xanthomonas outer protein D), a type III secreted effector from Xanthomonas campestris pv. vesicatoria, is a desumoylating enzyme with strict specificity for its plant small ubiquitin-like modifier (SUMO) substrates. Based on SUMO sequence alignments and peptidase assays with various plant, yeast, and mammalian SUMOs, we identified residues in SUMO that contribute to XopD/SUMO recognition...

We have analyzed the abundance of SUMO-conjugated species during the cell cycle in Xenopus egg extracts. The predominant SUMO conjugation products associated with mitotic chromosomes arose from SUMO conjugation of topoisomerase II. Topoisomerase II was modified exclusively by SUMO-2/3 during mitosis under normal circumstances, although we observed conjugation of topoisomerase II to SUMO-1 in ex...

SUMOylation is a post-translational modification that regulates a multitude of cellular processes, including replication, cell-cycle progression, protein transport and the DNA damage response. Similar to ubiquitin, SUMO (small ubiquitin-like modifier) is covalently attached to target proteins in a reversible process via an enzymatic cascade. SUMOylation is essential for nearly all eukaryotic or...

The small ubiquitin-like modifier (SUMO) can form polymeric chains that are important signals in cellular processes such as meiosis, genome maintenance and stress response. The SUMO-targeted ubiquitin ligase RNF4 engages with SUMO chains on linked substrates and catalyses their ubiquitination, which targets substrates for proteasomal degradation. Here we use a segmental labelling approach combi...

The small ubiquitin-related modifier (SUMO) system has been implicated in a number of biological functions, yet the individual components of the SUMO machinery involved in each of these activities were largely unknown. Here we report the first global SUMO system interactome. Using affinity purification coupled with mass spectrometry, we identify >450 protein-protein interactions surrounding the...

The small ubiquitin-like modifier 2 (SUMO-2) is required for survival when cells are exposed to treatments that induce proteotoxic stress by causing the accumulation of misfolded proteins. Exposure of cells to heat shock or other forms of proteotoxic stress induces the conjugation of SUMO-2 to proteins in the nucleus. We investigated the chromatin landscape of SUMO-2 modifications in response t...

SUMO, a small ubiquitin-related modifier, is known to covalently attach to a number of nuclear regulatory proteins such as p53, IkappaB, promyelocytic leukemia protein and c-Jun. The sumoylation reaction is catalyzed by the SUMO protease, which exposes the C-terminal active glycine residue of the nascent SUMO, the heterodimeric SUMO activating enzyme, the SUMO conjugating enzyme, Ubc9, and SUMO...

Three SUMO (small ubiquitin-related modifier) genes have been identified in humans, which tag proteins to modulate subcellular localization and/or enhance protein stability and activity. We report the identification of a novel intronless SUMO gene, SUMO-4, that encodes a 95-amino acid protein having an 86% amino acid homology with SUMO-2. In contrast to SUMO-2, which is highly expressed in all ...

Small ubiquitin-like modifier (SUMO) modification modulates the expression of defense genes in Drosophila, activated by the Toll/nuclear factor-κB and immune-deficient/nuclear factor-κB signaling networks. We have, however, limited understanding of the SUMO-modulated regulation of the immune response and lack information on SUMO targets in the immune system. In this study, we measured the chang...