Analysis of Yeast Killer Toxin K1 Precursor Processing via Site-Directed Mutagenesis: Implications for Toxicity and Immunity

ABSTRACT K1 represents a heterodimeric A/B toxin secreted by virus-infected Saccharomyces cerevisiae strains. In a two-staged receptor-mediated process, the ionophoric activity of K1 leads to an uncontrolled influx of protons, culminating in the breakdown of the cellular transmembrane potential of s...

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Autores principales:	Stefanie Gier, Manfred J. Schmitt, Frank Breinig
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2020
Materias:	K1 killer toxin yeast viral toxin Saccharomyces cerevisiae Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/0f31c069446848689bf4d49cf3f42a40
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spelling	oai:doaj.org-article:0f31c069446848689bf4d49cf3f42a402021-11-15T15:27:52ZAnalysis of Yeast Killer Toxin K1 Precursor Processing via Site-Directed Mutagenesis: Implications for Toxicity and Immunity10.1128/mSphere.00979-192379-5042https://doaj.org/article/0f31c069446848689bf4d49cf3f42a402020-02-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mSphere.00979-19https://doaj.org/toc/2379-5042ABSTRACT K1 represents a heterodimeric A/B toxin secreted by virus-infected Saccharomyces cerevisiae strains. In a two-staged receptor-mediated process, the ionophoric activity of K1 leads to an uncontrolled influx of protons, culminating in the breakdown of the cellular transmembrane potential of sensitive cells. K1 killer yeast necessitate not only an immunity mechanism saving the toxin-producing cell from its own toxin but, additionally, a molecular system inactivating the toxic α subunit within the secretory pathway. In this study, different derivatives of the K1 precursor were constructed to analyze the biological function of particular structural components and their influence on toxin activity as well as the formation of protective immunity. Our data implicate an inactivation of the α subunit during toxin maturation and provide the basis for an updated model of K1 maturation within the host cell’s secretory pathway. IMPORTANCE The killer phenotype in the baker’s yeast Saccharomyces cerevisiae relies on two double-stranded RNA viruses that are persistently present in the cytoplasm. As they carry the same receptor populations as sensitive cells, killer yeast cells need—in contrast to various bacterial toxin producers—a specialized immunity mechanism. The ionophoric killer toxin K1 leads to the formation of cation-specific pores in the plasma membrane of sensitive yeast cells. Based on the data generated in this study, we were able to update the current model of toxin processing, validating the temporary inactivation of the toxic α subunit during maturation in the secretory pathway of the killer yeast.Stefanie GierManfred J. SchmittFrank BreinigAmerican Society for MicrobiologyarticleK1killer toxinyeast viral toxinSaccharomyces cerevisiaeMicrobiologyQR1-502ENmSphere, Vol 5, Iss 1 (2020)
institution	DOAJ
collection	DOAJ
language	EN
topic	K1 killer toxin yeast viral toxin Saccharomyces cerevisiae Microbiology QR1-502
spellingShingle	K1 killer toxin yeast viral toxin Saccharomyces cerevisiae Microbiology QR1-502 Stefanie Gier Manfred J. Schmitt Frank Breinig Analysis of Yeast Killer Toxin K1 Precursor Processing via Site-Directed Mutagenesis: Implications for Toxicity and Immunity
description	ABSTRACT K1 represents a heterodimeric A/B toxin secreted by virus-infected Saccharomyces cerevisiae strains. In a two-staged receptor-mediated process, the ionophoric activity of K1 leads to an uncontrolled influx of protons, culminating in the breakdown of the cellular transmembrane potential of sensitive cells. K1 killer yeast necessitate not only an immunity mechanism saving the toxin-producing cell from its own toxin but, additionally, a molecular system inactivating the toxic α subunit within the secretory pathway. In this study, different derivatives of the K1 precursor were constructed to analyze the biological function of particular structural components and their influence on toxin activity as well as the formation of protective immunity. Our data implicate an inactivation of the α subunit during toxin maturation and provide the basis for an updated model of K1 maturation within the host cell’s secretory pathway. IMPORTANCE The killer phenotype in the baker’s yeast Saccharomyces cerevisiae relies on two double-stranded RNA viruses that are persistently present in the cytoplasm. As they carry the same receptor populations as sensitive cells, killer yeast cells need—in contrast to various bacterial toxin producers—a specialized immunity mechanism. The ionophoric killer toxin K1 leads to the formation of cation-specific pores in the plasma membrane of sensitive yeast cells. Based on the data generated in this study, we were able to update the current model of toxin processing, validating the temporary inactivation of the toxic α subunit during maturation in the secretory pathway of the killer yeast.
format	article
author	Stefanie Gier Manfred J. Schmitt Frank Breinig
author_facet	Stefanie Gier Manfred J. Schmitt Frank Breinig
author_sort	Stefanie Gier
title	Analysis of Yeast Killer Toxin K1 Precursor Processing via Site-Directed Mutagenesis: Implications for Toxicity and Immunity
title_short	Analysis of Yeast Killer Toxin K1 Precursor Processing via Site-Directed Mutagenesis: Implications for Toxicity and Immunity
title_full	Analysis of Yeast Killer Toxin K1 Precursor Processing via Site-Directed Mutagenesis: Implications for Toxicity and Immunity
title_fullStr	Analysis of Yeast Killer Toxin K1 Precursor Processing via Site-Directed Mutagenesis: Implications for Toxicity and Immunity
title_full_unstemmed	Analysis of Yeast Killer Toxin K1 Precursor Processing via Site-Directed Mutagenesis: Implications for Toxicity and Immunity
title_sort	analysis of yeast killer toxin k1 precursor processing via site-directed mutagenesis: implications for toxicity and immunity
publisher	American Society for Microbiology
publishDate	2020
url	https://doaj.org/article/0f31c069446848689bf4d49cf3f42a40
work_keys_str_mv	AT stefaniegier analysisofyeastkillertoxink1precursorprocessingviasitedirectedmutagenesisimplicationsfortoxicityandimmunity AT manfredjschmitt analysisofyeastkillertoxink1precursorprocessingviasitedirectedmutagenesisimplicationsfortoxicityandimmunity AT frankbreinig analysisofyeastkillertoxink1precursorprocessingviasitedirectedmutagenesisimplicationsfortoxicityandimmunity
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Analysis of Yeast Killer Toxin K1 Precursor Processing via Site-Directed Mutagenesis: Implications for Toxicity and Immunity

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