title: Kite Proteins: a Superfamily of SMC/Kleisin Partners Conserved Across Bacteria, Archaea, and Eukaryotes.
abstract: SMC/kleisin complexes form elongated annular structures, which are critical for chromosome segregation, genome maintenance, and the regulation of gene expression. We describe marked structural similarities between bacterial and eukaryotic SMC/kleisin partner proteins (designated here as "kite" proteins for kleisin interacting tandem winged-helix (WH) elements of SMC complexes). Kite proteins are integral parts of all prokaryotic SMC complexes and Smc5/6 but not cohesin and condensin. They are made up of tandem WH domains, form homo- or heterodimers via their amino-terminal WH domain, and they associate with the central part of a kleisin subunit. In placental mammals, the kite subunit NSE3 gave rise to several (>60) kite-related proteins, named MAGE, many of which encode tumor- and testis-specific antigens. Based on architectural rather than sequence similarity, we propose an adapted model for the evolution of the SMC protein complexes and discuss potential functional similarities between bacterial Smc/ScpAB and eukaryotic Smc5/6.
authors.affiliation: Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic; Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic. Electronic address: jpalecek@sci.muni.cz.
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Palecek
authors.affiliation: Max Planck Institute of Biochemistry, Chromosome Organization and Dynamics, Am Klopferspitz 18, 82152 Martinsried, Germany. Electronic address: sgruber@biochem.mpg.de.
authors.forename: Stephan
authors.initials: S
authors.lastname: Gruber
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D016547:Kinesins / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D016547:Kinesins
keywords: MAGE; MksBEF; MukBEF; SMC; Smc/ScpAB; Smc5/6; chromosome segregation; cohesin; cohesion; condensation; condensin; kite proteins; kleisin; replication; structural maintenance of chromosomes; winged helix domains