TY - JOUR
T1 - An improved SUMmOn-based methodology for the identification of ubiquitin and ubiquitin-like protein conjugation sites identifies novel ubiquitin-like protein chain linkages
AU - Jeram, Stanley M
AU - Srikumar, Tharan
AU - Zhang, Xiang-Dong
AU - Eisenhauer, H Anne
AU - Rogers, Richard
AU - Pedrioli, Patrick G A
AU - Matunis, Michael
AU - Raught, Brian
PY - 2010
Y1 - 2010
N2 - Ubiquitin (Ub) and the ubiquitin-like proteins (Ubls) comprise a remarkable assortment of polypeptides that are covalently conjugated to target proteins (or other biomolecules) to modulate their intracellular localization, half-life, and/or activity. Identification of Ub/Ubl conjugation sites on a protein of interest can thus be extremely important for understanding how it is regulated. While MS has become a powerful tool for the study of many classes of PTMs, the identification of Ub/Ubl conjugation sites presents a number of unique challenges. Here, we present an improved Ub/Ubl conjugation site identification strategy, utilizing SUMmOn analysis and an additional protease (lysyl endopeptidase C), as a complement to standard approaches. As compared with standard trypsin proteolysis-database search protocols alone, the addition of SUMmOn analysis can (i) identify Ubl conjugation sites that are not detected by standard database searching methods, (ii) better preserve Ub/Ubl conjugate identity, and (iii) increase the number of identifications of Ub/Ubl modifications in lysine-rich protein regions. Using this methodology, we characterize for the first time a number of novel Ubl linkages and conjugation sites, including alternative yeast (K54) and mammalian small ubiquitin-related modifier (SUMO) chain (SUMO-2 K42, SUMO-3 K41) assemblies, as well as previously unreported NEDD8 chain (K27, K33, and K54) topologies.
AB - Ubiquitin (Ub) and the ubiquitin-like proteins (Ubls) comprise a remarkable assortment of polypeptides that are covalently conjugated to target proteins (or other biomolecules) to modulate their intracellular localization, half-life, and/or activity. Identification of Ub/Ubl conjugation sites on a protein of interest can thus be extremely important for understanding how it is regulated. While MS has become a powerful tool for the study of many classes of PTMs, the identification of Ub/Ubl conjugation sites presents a number of unique challenges. Here, we present an improved Ub/Ubl conjugation site identification strategy, utilizing SUMmOn analysis and an additional protease (lysyl endopeptidase C), as a complement to standard approaches. As compared with standard trypsin proteolysis-database search protocols alone, the addition of SUMmOn analysis can (i) identify Ubl conjugation sites that are not detected by standard database searching methods, (ii) better preserve Ub/Ubl conjugate identity, and (iii) increase the number of identifications of Ub/Ubl modifications in lysine-rich protein regions. Using this methodology, we characterize for the first time a number of novel Ubl linkages and conjugation sites, including alternative yeast (K54) and mammalian small ubiquitin-related modifier (SUMO) chain (SUMO-2 K42, SUMO-3 K41) assemblies, as well as previously unreported NEDD8 chain (K27, K33, and K54) topologies.
U2 - 10.1002/pmic.200900648
DO - 10.1002/pmic.200900648
M3 - Article
C2 - 20029837
SN - 1615-9861
VL - 10
SP - 254
EP - 265
JO - Proteomics
JF - Proteomics
IS - 2
ER -