Coupled synthesis and translocation restrains polyphosphate to acidocalcisome-like vacuoles and prevents its toxicity.

Détails

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Etat: Public
Version: de l'auteur
ID Serval
serval:BIB_97FEDD1E48BE
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Coupled synthesis and translocation restrains polyphosphate to acidocalcisome-like vacuoles and prevents its toxicity.
Périodique
Journal of Cell Science
Auteur(s)
Gerasimaitė R., Sharma S., Desfougères Y., Schmidt A., Mayer A.
ISSN
1477-9137 (Electronic)
ISSN-L
0021-9533
Statut éditorial
Publié
Date de publication
2014
Volume
127
Numéro
23
Pages
5093-5104
Langue
anglais
Résumé
Eukaryotes contain inorganic polyphosphate (polyP) and acidocalcisomes, which sequester polyP and store amino acids and divalent cations. Why polyP is sequestered in dedicated organelles is not known. We show that polyP produced in the cytosol of yeast becomes toxic. Reconstitution of polyP translocation with purified vacuoles, the acidocalcisomes of yeast, shows that cytosolic polyP cannot be imported, whereas polyP produced by the vacuolar transporter chaperone (VTC) complex, an endogenous vacuolar polyP polymerase, is efficiently imported and does not interfere with growth. PolyP synthesis and import require an electrochemical gradient, probably as a driving force for polyP translocation. VTC exposes its catalytic domain to the cytosol and carries nine vacuolar transmembrane domains. Mutations in the VTC transmembrane regions, which are likely to constitute the translocation channel, block not only polyP translocation but also synthesis. Given that they are far from the cytosolic catalytic domain of VTC, this suggests that the VTC complex obligatorily couples synthesis of polyP to its import in order to avoid toxic intermediates in the cytosol. Sequestration of otherwise toxic polyP might be one reason for the existence of acidocalcisomes in eukaryotes.
Mots-clé
Yeast vacuole, Inorganic polyphosphate, VTC complex, Acidocalcisome
Pubmed
Web of science
Open Access
Oui
Création de la notice
02/01/2015 9:32
Dernière modification de la notice
20/08/2019 14:59
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