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Shu1 is a cell-surface protein involved in iron acquisition from heme in Schizosaccharomyces pombe.
- Source :
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The Journal of biological chemistry [J Biol Chem] 2015 Apr 17; Vol. 290 (16), pp. 10176-90. Date of Electronic Publication: 2015 Mar 02. - Publication Year :
- 2015
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Abstract
- Iron is an essential metal cofactor that is required for many biological processes. Eukaryotic cells have consequently developed different strategies for its acquisition. Until now, Schizosaccharomyces pombe was known to use reductive iron uptake and siderophore-bound iron transport to scavenge iron from the environment. Here, we report the identification of a gene designated shu1(+) that encodes a protein that enables S. pombe to take up extracellular heme for cell growth. When iron levels are low, the transcription of shu1(+) is induced, although its expression is repressed when iron levels rise. The iron-dependent down-regulation of shu1(+) requires the GATA-type transcriptional repressor Fep1, which strongly associates with a proximal promoter region of shu1(+) in vivo in response to iron repletion. HA4-tagged Shu1 localizes to the plasma membrane in cells expressing a functional shu1(+)-HA4 allele. When heme biosynthesis is selectively blocked in mutated S. pombe cells, their ability to acquire exogenous hemin or the fluorescent heme analog zinc mesoporphyrin IX is dependent on the expression of Shu1. Further analysis by absorbance spectroscopy and hemin-agarose pulldown assays showed that Shu1 interacts with hemin, with a KD of ∼2.2 μm. Taken together, results reported here revealed that S. pombe possesses an unexpected pathway for heme assimilation, which may also serve as a source of iron for cell growth.<br /> (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)
- Subjects :
- Cell Membrane metabolism
GATA Transcription Factors genetics
GATA Transcription Factors metabolism
Hemin metabolism
Ion Transport
Membrane Transport Proteins metabolism
Metalloporphyrins metabolism
Oxidation-Reduction
Recombinant Fusion Proteins genetics
Recombinant Fusion Proteins metabolism
Schizosaccharomyces metabolism
Schizosaccharomyces pombe Proteins metabolism
Signal Transduction
Gene Expression Regulation, Fungal
Heme metabolism
Iron metabolism
Membrane Transport Proteins genetics
Schizosaccharomyces genetics
Schizosaccharomyces pombe Proteins genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1083-351X
- Volume :
- 290
- Issue :
- 16
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 25733668
- Full Text :
- https://doi.org/10.1074/jbc.M115.642058