Dataset Information

IDENTIFICATION OF SUMO-2/3 MODIFIED PROTEINS ASSOCIATED WITH MITOTIC CHROMOSOMES

ABSTRACT: Sumoylation is essential for progression through mitosis, but the specific protein targets and functions remain poorly understood. In this study, we used chromosome spreads to more precisely define the localization of SUMO-2/3 to the inner-centromere and protein scaffold of mitotic chromosomes. We also developed methods to immune-purify proteins modified by endogenous, untagged SUMO-2/3 from mitotic chromosomes. Using these methods we identified 149 chromosome associated SUMO-2/3 substrates by nLC-ESI-MS/MS. Approximately one-third of the identified proteins have reported functions in mitosis. Consistent with SUMO-2/3 immunolocalization, we identified known centromere and kinetochore associated proteins, as well as chromosome scaffold associated proteins. Notably, >30 proteins involved in chromatin modification or remodeling were identified. Our results provide insights into the roles of sumoylation as a regulator of chromatin structure and other diverse processes in mitosis. Furthermore, our purification and fractionation methodologies represent an important compliment to existing approaches to identify sumoylated proteins using exogenously expressed and tagged SUMOs.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Homo Sapiens (ncbitaxon:9606)

SUBMITTER: Michael Matunis

PROVIDER: MSV000078890 | MassIVE | Tue Oct 07 09:24:00 BST 2014

SECONDARY ACCESSION(S): PXD001534

REPOSITORIES: MassIVE

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Publications

Identification of SUMO-2/3-modified proteins associated with mitotic chromosomes.

Cubeñas-Potts Caelin C Srikumar Tharan T Lee Christine C Osula Omoruyi O Subramonian Divya D Zhang Xiang-Dong XD Cotter Robert J RJ Raught Brian B Matunis Michael J MJ

Proteomics 20150107 4

Sumoylation is essential for progression through mitosis, but the specific protein targets and functions remain poorly understood. In this study, we used chromosome spreads to more precisely define the localization of SUMO-2/3 (small ubiquitin-related modifier) to the inner centromere and protein scaffold of mitotic chromosomes. We also developed methods to immunopurify proteins modified by endogenous, untagged SUMO-2/3 from mitotic chromosomes. Using these methods, we identified 149 chromosome- ...[more]

PMID: 25367092

Similar Datasets

Project description:SUMO modification of proteins (sumoylation) is essential for mitotic progression from yeast to humans, but only a limited number of sumoylated proteins with functions in mitosis have been discovered. Vertebrates express three SUMO paralogs, SUMO-1, SUMO-2 and SUMO-3, but only SUMO-2 and -3 are chromosome-associated in mitosis. In this study, we used chromosome spreads to more precisely define the localization of endogenous SUMO-2 and -3 to the centromere as well as the chromosome protein scaffold. Furthermore, we developed methodologies for the immunopurification of endogenous SUMO-2 and -3 modified proteins from cell extracts. Using LC-MS/MS, we analyzed proteins immunopurified from mitotic chromosome fractions and G0 nuclear fractions. We identified 296 putative sumoylated proteins, with 138 being modified specifically in mitosis. We identified proteins known to localize to the centromere and kinetochore and the chromosome protein scaffold, consistent with SUMO-2/3 localization. Furthermore, we demonstrate that utilizing cell synchronization and fractionation allowed for the discovery of low abundance sumoylated proteins that are not detected in large asynchronous analyses. Our results provide a foundation for further characterization of the roles of sumoylation in regulating diverse aspects of chromosome segregation in mitosis. Thermo .raw files were uploaded to the ProHits (Liu et al, 2010) analytical suite and converted to .mzXML format using ReAdW software. Data were searched using X!Tandem (Craig & Beavis, 2004) against human ORFs (RefSeq v45). Search parameters specified a parent MS tolerance of +/- 15ppm, and an MS/MS tolerance of 0.4 Da, with up to two missed cleavages for trypsin. Oxidation of methionine and tryptophan, ubiquitylation of lysine, and alkylation of cysteine (by NEM) were allowed as variable modifications. Statistical validation of the results was performed using Peptide Prophet and Protein Prophet (Keller et al, 2002; Nesvizhskii et al, 2003) as part of the trans-proteomic pipeline. For each search, the Protein Prophet probability at a 1% false discovery rate was used as a cutoff value to generate SAINT-compatible input files. SAINT parameters were as follows: 5000 iterations, low mode Off (0), minFold 1 and normalization (1) (Choi et al, 2011). SAINT cutoff values of 0.75 were used to generate a high-confidence list of protein identifications.