title: Characterization of the structures involved in localization of the SUN proteins to the nuclear envelope and the centrosome.
abstract: The nuclear envelope forms a selective barrier that separates the cytoplasm from the nucleus. During mitosis the nuclear envelope breaks down so that the microtubule network can form contacts with the kinetochore and guide chromosome segregation. Previous studies have suggested a model in which the centrosome and the microtubule network may play a role in nuclear envelope breakdown through as yet unidentified interactions with proteins localized to the nuclear envelope. In the current study we characterized a nuclear envelope protein SUN2 and identified a substructure involved in its localization to the nuclear envelope. We found that a structurally related protein, SUN1, may be localized to the nuclear envelope through a different mechanism. Furthermore, the SUN2 protein can form different assemblies, including homodimers and heterodimers with SUN1. Finally, we provide evidence indicating that SUN1 and SUN2 may form a physical interaction between the nuclear envelope and the centrosome.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA. wangq252@mail.med.upenn.edu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.forename: Xiulian
authors.initials: X
authors.lastname: Du
authors.forename: Zheng
authors.initials: Z
authors.lastname: Cai
authors.forename: Mark I
authors.initials: MI
authors.lastname: Greene
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D018385:Centrosome / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009685:Nuclear Envelope / Q000378:metabolism*; D009687:Nuclear Proteins; D011485:Protein Binding
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; C506117:SUN1 protein, human; C464932:SUN1 protein, mouse; C413025:SUN2 protein, human