title: Protection from isopeptidase-mediated deconjugation regulates paralog-selective sumoylation of RanGAP1.
abstract: Vertebrates express three small ubiquitin-related modifiers (SUMO-1, SUMO-2, and SUMO-3) that are conjugated in part to unique subsets of proteins and, thereby, regulate distinct cellular processes. Mechanisms regulating paralog-selective sumoylation, however, remain poorly understood. Despite being equally well modified by SUMO-1 and SUMO-2 in vitro, RanGAP1 is selectively modified by SUMO-1 in vivo. We have found that this paralog-selective modification is determined at the level of deconjugation by isopeptidases. Our findings indicate that, relative to SUMO-2-modified RanGAP1, SUMO-1-modified RanGAP1 forms a more stable, higher affinity complex with the nucleoporin Nup358/RanBP2 that preferentially protects it from isopeptidases. By swapping residues in SUMO-1 and SUMO-2 responsible for Nup358/RanBP2 binding, or by manipulating isopeptidase expression levels, paralog-selective modification of RanGAP1 could be affected both in vitro and in vivo. Thus, protection from isopeptidases, through interactions with SUMO-binding proteins, represents an important mechanism defining paralog-selective sumoylation.
authors.affiliation: Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Zhu
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Goeres
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Sixt
authors.forename: Miklós
authors.initials: M
authors.lastname: Békés
authors.forename: Xiang-Dong
authors.initials: XD
authors.lastname: Zhang
authors.forename: Guy S
authors.initials: GS
authors.lastname: Salvesen
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Matunis
mesh_terms: D000818:Animals; D019759:Carbon-Nitrogen Lyases / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000378:metabolism; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism / Q000494:pharmacology; D025842:SUMO-1 Protein / Q000378:metabolism; D025841:Small Ubiquitin-Related Modifier Proteins / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D020690:GTPase-Activating Proteins; D018832:Molecular Chaperones; D028861:Nuclear Pore Complex Proteins; D034741:RNA, Small Interfering; C085844:Rangap1 protein, mouse; D011993:Recombinant Fusion Proteins; D025842:SUMO-1 Protein; D025841:Small Ubiquitin-Related Modifier Proteins; C094493:ran-binding protein 2; D044763:Ubiquitin-Conjugating Enzymes; D003546:Cysteine Endopeptidases; C118083:Ulp1 protease; D019759:Carbon-Nitrogen Lyases; C034300:isopeptidase; D000098843:Ubiquitin-Conjugating Enzyme UBC9