title: Newly Characterized Region of CP190 Associates with Microtubules and Mediates Proper Spindle Morphology in Drosophila Stem Cells.
abstract: CP190 is a large, multi-domain protein, first identified as a centrosome protein with oscillatory localization over the course of the cell cycle. During interphase it has a well-established role within the nucleus as a chromatin insulator. Upon nuclear envelope breakdown, there is a striking redistribution of CP190 to centrosomes and the mitotic spindle, in addition to the population at chromosomes. Here, we investigate CP190 in detail by performing domain analysis in cultured Drosophila S2 cells combined with protein structure determination by X-ray crystallography, in vitro biochemical characterization, and in vivo fixed and live imaging of cp190 mutant flies. Our analysis of CP190 identifies a novel N-terminal centrosome and microtubule (MT) targeting region, sufficient for spindle localization. This region consists of a highly conserved BTB domain and a linker region that serves as the MT binding domain. We present the 2.5 Å resolution structure of the CP190 N-terminal 126 amino acids, which adopts a canonical BTB domain fold and exists as a stable dimer in solution. The ability of the linker region to robustly localize to MTs requires BTB domain-mediated dimerization. Deletion of the linker region using CRISPR significantly alters spindle morphology and leads to DNA segregation errors in the developing Drosophila brain neuroblasts. Collectively, we highlight a multivalent MT-binding architecture in CP190, which confers distinct subcellular cytoskeletal localization and function during mitosis.
authors.affiliation: Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, 20892, United State of America.|Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, 27599, United States of America.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Plevock
authors.affiliation: Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, 20892, United State of America.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Galletta
authors.affiliation: Department of Biology, University of North Carolina, Chapel Hill, North Carolina, 27599, United States of America.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Slep
authors.affiliation: Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, 20892, United State of America.
authors.forename: Nasser M
authors.initials: NM
authors.lastname: Rusan
mesh_terms: D000818:Animals; D002467:Cell Nucleus; D018385:Centrosome; D020090:Chromosome Segregation; D002875:Chromosomes; D064112:Clustered Regularly Interspaced Short Palindromic Repeats; D018360:Crystallography, X-Ray; D004247:DNA / Q000378:metabolism; D029721:Drosophila Proteins / Q000502:physiology*; D004331:Drosophila melanogaster / Q000235:genetics*; D008869:Microtubule-Associated Proteins / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology*; D009687:Nuclear Proteins / Q000502:physiology*; D008941:Spindle Apparatus / Q000378:metabolism / Q000648:ultrastructure*; D013234:Stem Cells / Q000378:metabolism
chemical_list: C107964:CP190 protein, Drosophila; D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D004247:DNA