Cellular iron utilization is regulated by putative siderophore transporter FgSit1 not by free iron transporter in Fusarium graminearum

Biochem Biophys Res Commun. 2006 Jul 14;345(4):1634-42. doi: 10.1016/j.bbrc.2006.05.071. Epub 2006 May 19.

Abstract

This report investigated FgSit1, which encodes a putative ferrichrome transporter of Fusarium graminearum. The identity of the deduced amino acid sequence of FgSit1 with the amino acid sequence of ScArn1p, an FC-Fe(3+) transporter of Saccharomyces cerevisiae, was 51%; both the growth defect related to the Deltafet3Deltaarn1-4 strain of S. cerevisiae in an iron-depleted condition and the FC-Fe(3+) uptake activity were recovered upon the introduction of FgSit1 into the Deltafet3Deltaarn1-4 strain. Although ScArn1p was found in the late endosomal compartment in S. cerevisiae, FgSit1 was found on the plasma membrane in S. cerevisiae; when FgSit1 was expressed exogenously in S. cerevisiae, it showed greater FC-Fe(3+) uptake activity than did ScArn1p. Additionally, in F. graminearum FC-Fe(3+) uptake activity in the Deltafgsit1 strain was found to be one-fourth that of the wild-type. However, Fe(3+) uptake activity in the Deltafgsit1 strain was 5-fold higher than that of wild-type; the gene expression of FgFtr1, a putative iron transporter, was induced by the deletion of FgSit1, but was not induced by the deletion of FgSit2. Taken together, these results strongly suggest that FgSit1 encodes a putative FC-Fe(3+) transporter that mediates FC-Fe(3+) uptake using a different mechanism than ScArn1p and plays an important role in the regulation of cellular iron availability in F. graminearum.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Biological Transport
  • Blotting, Northern
  • Cell Membrane / metabolism
  • Ferrichrome / metabolism
  • Fusarium / drug effects
  • Fusarium / genetics
  • Fusarium / metabolism*
  • Gene Expression Regulation, Fungal / drug effects
  • Genetic Complementation Test
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Iron / metabolism
  • Iron / pharmacokinetics*
  • Iron / pharmacology
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / physiology*
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • Mutation
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae / metabolism
  • Sequence Homology, Amino Acid
  • Siderophores / metabolism*
  • Transformation, Genetic

Substances

  • Membrane Transport Proteins
  • Recombinant Fusion Proteins
  • Siderophores
  • Green Fluorescent Proteins
  • Ferrichrome
  • Iron