title: The Neurospora organelle motor: a distant relative of conventional kinesin with unconventional properties.
abstract: The "conventional" kinesins comprise a conserved family of molecular motors for organelle transport that have been identified in various animal species. Organelle motors from other phyla have not yet been analyzed at the molecular level. Here we report the identification, biochemical and immunological characterization, and molecular cloning of a cytoplasmic motor in a "lower" eukaryote, the Ascomycete fungus Neurospora crassa. This motor, termed Nkin (for Neurospora kinesin), exhibits several unique structural and functional features, including a high rate of microtubule transport, a lack of copurifying light chains, a second P-loop motif, and an overall sequence organization reminiscent of a kinesin-like protein. However, a greater than average sequence homology in the motor domain and the presence of a highly conserved region in the C-terminus identify Nkin as a distant relative of the family of conventional kinesins. A molecular phylogenetic analysis suggests Nkin to have diverged early in the evolution of this family of motors. The discovery of Nkin may help identify domains important for specific biological functions in conventional kinesins.
authors.affiliation: Institute for Cell Biology, University of Munich, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Steinberg
authors.forename: M
authors.initials: M
authors.lastname: Schliwa
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D015153:Blotting, Western; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D017931:DNA Primers; D004330:Drosophila; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D016547:Kinesins / Q000096:biosynthesis / Q000302:isolation & purification / Q000502:physiology*; D008870:Microtubules / Q000502:physiology / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009068:Movement; D009492:Neurospora crassa / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure*; D015388:Organelles / Q000502:physiology* / Q000648:ultrastructure*; D016133:Polymerase Chain Reaction; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D000251:Adenosine Triphosphatases; D016547:Kinesins