title: Coiled-coil protein composition of 22 proteomes--differences and common themes in subcellular infrastructure and traffic control.
abstract: BACKGROUND
  Long alpha-helical coiled-coil proteins are involved in diverse organizational and regulatory processes in eukaryotic cells. They provide cables and networks in the cyto- and nucleoskeleton, molecular scaffolds that organize membrane systems and tissues, motors, levers, rotating arms, and possibly springs. Mutations in long coiled-coil proteins have been implemented in a growing number of human diseases. Using the coiled-coil prediction program MultiCoil, we have previously identified all long coiled-coil proteins from the model plant Arabidopsis thaliana and have established a searchable Arabidopsis coiled-coil protein database.
  
  
  RESULTS
  Here, we have identified all proteins with long coiled-coil domains from 21 additional fully sequenced genomes. Because regions predicted to form coiled-coils interfere with sequence homology determination, we have developed a sequence comparison and clustering strategy based on masking predicted coiled-coil domains. Comparing and grouping all long coiled-coil proteins from 22 genomes, the kingdom-specificity of coiled-coil protein families was determined. At the same time, a number of proteins with unknown function could be grouped with already characterized proteins from other organisms.
  
  
  CONCLUSIONS
  MultiCoil predicts proteins with extended coiled-coil domains (more than 250 amino acids) to be largely absent from bacterial genomes, but present in archaea and eukaryotes. The structural maintenance of chromosomes proteins and their relatives are the only long coiled-coil protein family clearly conserved throughout all kingdoms, indicating their ancient nature. Motor proteins, membrane tethering and vesicle transport proteins are the dominant eukaryote-specific long coiled-coil proteins, suggesting that coiled-coil proteins have gained functions in the increasingly complex processes of subcellular infrastructure maintenance and trafficking control of the eukaryotic cell.
authors.affiliation: Department of Plant Cellular and Molecular Biology, Plant Biotechnology Center, Ohio State University, Columbus, OH 43210, USA. rose.273@osu.edu
authors.forename: Annkatrin
authors.initials: A
authors.lastname: Rose
authors.forename: Shannon J
authors.initials: SJ
authors.lastname: Schraegle
authors.forename: Eric A
authors.initials: EA
authors.lastname: Stahlberg
authors.forename: Iris
authors.initials: I
authors.lastname: Meier
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D029681:Arabidopsis Proteins / Q000737:chemistry*; D001426:Bacterial Proteins; D002352:Carrier Proteins; D002462:Cell Membrane / Q000378:metabolism; D016000:Cluster Analysis; D003599:Cytoskeleton / Q000378:metabolism; D030562:Databases, Protein; D019143:Evolution, Molecular; D017343:Genes, Plant; D016678:Genome; D020745:Genome, Archaeal; D006801:Humans; D008954:Models, Biological; D008957:Models, Genetic; D010802:Phylogeny; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011506:Proteins; D020543:Proteome; D040901:Proteomics / Q000379:methods*; D017422:Sequence Analysis, DNA; D012984:Software; D013045:Species Specificity
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D011506:Proteins; D020543:Proteome