title: Nic1p, a relative of bacterial transition metal permeases in Schizosaccharomyces pombe, provides nickel ion for urease biosynthesis.
abstract: The Schizosaccharomyces pombe genome sequencing project identified an open reading frame (O74869 and O74912, named Nic1p in the present study) with significant similarity to members of a family of bacterial transition metal permeases. These uptake systems transport Ni(2+) ion with extremely high affinity across the bacterial cytoplasmic membrane, but they differ in selectivity toward divalent transition metal cations. An S. pombe mutant harboring an interrupted nic1 allele (nic1-1) was strongly impaired in (63)Ni(2+) uptake in the presence of a high molar ratio of Mg(2+) relative to Ni(2+), conditions that reflect the natural situation. Under these conditions, the nic1-1 mutant contained only background activities of the nickel-dependent cytoplasmic enzyme urease and could not catabolize urea. Among a series of divalent transition metal cations tested (Cd(2+), Co(2+), Cu(2+), Mn(2+), and Zn(2+)), only Co(2+) caused considerable inhibition of Nic1p-mediated Ni(2+) uptake. On the other hand, experiments with (57)Co(2+) (at nm concentrations) did not show significant differences in Co(2+) uptake between the nic1-1 mutant and the parental strain. Our data suggest that Nic1p acts as a plasma-membrane nickel transporter in fission yeast, a finding that invites searches for isologous counterparts in higher eukaryotes.
authors.affiliation: Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany. thomas.eitinger@rz.hu-berlin.de
authors.forename: T
authors.initials: T
authors.lastname: Eitinger
authors.forename: O
authors.initials: O
authors.lastname: Degen
authors.forename: U
authors.initials: U
authors.lastname: Bohnke
authors.forename: M
authors.initials: M
authors.lastname: Muller
mesh_terms: D000595:Amino Acid Sequence; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D027682:Cation Transport Proteins; D003035:Cobalt / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009532:Nickel / Q000378:metabolism*; D016366:Open Reading Frames; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D016415:Sequence Alignment; D014510:Urease / Q000096:biosynthesis*
chemical_list: D002352:Carrier Proteins; D027682:Cation Transport Proteins; D008565:Membrane Proteins; C410739:Nic1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D003035:Cobalt; D009532:Nickel; D014510:Urease; C018021:cobaltous chloride