title: 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 (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-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.
authors.affiliation: Department of Biochemistry & Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Caelin
authors.initials: C
authors.lastname: Cubeñas-Potts
authors.forename: Tharan
authors.initials: T
authors.lastname: Srikumar
authors.forename: Christine
authors.initials: C
authors.lastname: Lee
authors.forename: Omoruyi
authors.initials: O
authors.lastname: Osula
authors.forename: Divya
authors.initials: D
authors.lastname: Subramonian
authors.forename: Xiang-Dong
authors.initials: XD
authors.lastname: Zhang
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Cotter
authors.forename: Brian
authors.initials: B
authors.lastname: Raught
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Matunis
mesh_terms: D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D002875:Chromosomes / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis / Q000502:physiology*; D060066:Protein Interaction Maps; D040901:Proteomics; D015203:Reproducibility of Results; D025841:Small Ubiquitin-Related Modifier Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D058207:Sumoylation / Q000502:physiology*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; C117909:SUMO2 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins
keywords: Cell biology; Chromosome; Mitosis; SUMO