Fission yeast cells deficient in siderophore biosynthesis require Str2 for ferrichrome-dependent growth

Ferrichrome (Fc) acquisition in Schizosaccharomyces pombe is mediated by the cell-surface siderophore-iron transporter Str1. Here, we report that Str2, a protein homologous to Str1, localizes to the vacuolar membrane. Like Str1, Str2 expression is transcriptionally regulated in response to changes i...

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Main Authors: Berthy Mbuya, Samuel Plante, Tobias Vahsen, Ariane Brault, Simon Labbé
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-02-01
Series:Frontiers in Microbiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2025.1527727/full
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author Berthy Mbuya
Samuel Plante
Tobias Vahsen
Ariane Brault
Simon Labbé
author_facet Berthy Mbuya
Samuel Plante
Tobias Vahsen
Ariane Brault
Simon Labbé
author_sort Berthy Mbuya
collection DOAJ
description Ferrichrome (Fc) acquisition in Schizosaccharomyces pombe is mediated by the cell-surface siderophore-iron transporter Str1. Here, we report that Str2, a protein homologous to Str1, localizes to the vacuolar membrane. Like Str1, Str2 expression is transcriptionally regulated in response to changes in iron concentrations. Both the str2+ and str1+ genes are induced under low-iron conditions and are repressed by the iron-responsive GATA-type transcription factor Fep1 when iron is abundant. Under high-iron conditions, chromatin immunoprecipitation (ChIP) assays reveal that TAP-Fep1 occupies the str2+ and str1+ promoters. Isolated vacuoles from str2Δ fep1Δ cells expressing GFP-tagged Str2 exhibit iron accumulation in vacuoles upon exposure to exogenous holo-Fc. sib1Δ sib2Δ cells deficient in Fc biosynthesis and lacking the str2+ gene (str2Δ) are unable to grow in the presence of exogenous Fc as a sole source of iron. Further analysis identified that conserved amino acids Tyr539 and Tyr553 in the last predicted loop of Str2 are required for supporting Fc-dependent growth of a sib1Δ sib2Δ mutant strain. Collectively, these findings indicate that the vacuolar Str2 protein plays a role in the consumption of Fc as an iron source, while also revealing the involvement of the vacuole in iron release from exogenous Fc after its assimilation.
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spelling doaj-art-2b38a99c86594eb2b45b7143e1d72caa2025-02-06T12:12:37ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2025-02-011610.3389/fmicb.2025.15277271527727Fission yeast cells deficient in siderophore biosynthesis require Str2 for ferrichrome-dependent growthBerthy MbuyaSamuel PlanteTobias VahsenAriane BraultSimon LabbéFerrichrome (Fc) acquisition in Schizosaccharomyces pombe is mediated by the cell-surface siderophore-iron transporter Str1. Here, we report that Str2, a protein homologous to Str1, localizes to the vacuolar membrane. Like Str1, Str2 expression is transcriptionally regulated in response to changes in iron concentrations. Both the str2+ and str1+ genes are induced under low-iron conditions and are repressed by the iron-responsive GATA-type transcription factor Fep1 when iron is abundant. Under high-iron conditions, chromatin immunoprecipitation (ChIP) assays reveal that TAP-Fep1 occupies the str2+ and str1+ promoters. Isolated vacuoles from str2Δ fep1Δ cells expressing GFP-tagged Str2 exhibit iron accumulation in vacuoles upon exposure to exogenous holo-Fc. sib1Δ sib2Δ cells deficient in Fc biosynthesis and lacking the str2+ gene (str2Δ) are unable to grow in the presence of exogenous Fc as a sole source of iron. Further analysis identified that conserved amino acids Tyr539 and Tyr553 in the last predicted loop of Str2 are required for supporting Fc-dependent growth of a sib1Δ sib2Δ mutant strain. Collectively, these findings indicate that the vacuolar Str2 protein plays a role in the consumption of Fc as an iron source, while also revealing the involvement of the vacuole in iron release from exogenous Fc after its assimilation.https://www.frontiersin.org/articles/10.3389/fmicb.2025.1527727/fullfission yeastferrichromeironiron-regulatory GATA-type transcription factorsiderophore transporter
spellingShingle Berthy Mbuya
Samuel Plante
Tobias Vahsen
Ariane Brault
Simon Labbé
Fission yeast cells deficient in siderophore biosynthesis require Str2 for ferrichrome-dependent growth
Frontiers in Microbiology
fission yeast
ferrichrome
iron
iron-regulatory GATA-type transcription factor
siderophore transporter
title Fission yeast cells deficient in siderophore biosynthesis require Str2 for ferrichrome-dependent growth
title_full Fission yeast cells deficient in siderophore biosynthesis require Str2 for ferrichrome-dependent growth
title_fullStr Fission yeast cells deficient in siderophore biosynthesis require Str2 for ferrichrome-dependent growth
title_full_unstemmed Fission yeast cells deficient in siderophore biosynthesis require Str2 for ferrichrome-dependent growth
title_short Fission yeast cells deficient in siderophore biosynthesis require Str2 for ferrichrome-dependent growth
title_sort fission yeast cells deficient in siderophore biosynthesis require str2 for ferrichrome dependent growth
topic fission yeast
ferrichrome
iron
iron-regulatory GATA-type transcription factor
siderophore transporter
url https://www.frontiersin.org/articles/10.3389/fmicb.2025.1527727/full
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AT samuelplante fissionyeastcellsdeficientinsiderophorebiosynthesisrequirestr2forferrichromedependentgrowth
AT tobiasvahsen fissionyeastcellsdeficientinsiderophorebiosynthesisrequirestr2forferrichromedependentgrowth
AT arianebrault fissionyeastcellsdeficientinsiderophorebiosynthesisrequirestr2forferrichromedependentgrowth
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