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Article Dans Une Revue Letters in Applied NanoBioScience Année : 2015

Combining atomic force microscopy and genetics to investigate the role of KNR4 in Saccharomyces Cerevisiae sensitivity to K9 killer toxin

Résumé

K9 killer toxin is a small peptide secreted by the yeast Williopsis saturnus var: mrakii (previously known as Hansenula mrakii) with a strong cytocidal activity against sensitive yeast strains, including Saccharomyces cerevisiae. Treatment with this toxin results in the formation of pores at the surface of the cells, and more specifically at places where cell wall synthesis is the most active, namely at the tip of growing buds or mating projections. Yeast cells treated with K9 toxin then die by releasing cytoplasm and cellular materials from these pores. In the yeast S. cerevisiae, KNR4 protein localizes at the sites of polarized growth (bud tips, shmoo tips), which are also the sites where the toxin forms pores in the cell wall. Mutants defective in KNR4 gene are remarkably resistant to this toxin. In this study, we analyzed for the first time the biophysical effects of K9 on the yeast cell wall using Atomic Force Microscopy (AFM), a cutting edge technology that allows measuring the nanomechanical properties of living yeast cells, and their alterations by various drugs. To this end, we measured the effects of K9 toxin on the nanomechanical properties of the cell wall of S. cerevisiae wild-type cells and mutants deleted for KNR4 gene, at the short (2 h) and long term (20 h). Our results reveal an important cell wall remodeling occurring in wild- type cells already after 2 hours and only visible in knr4 mutant after 20 hours of treatment. Moreover, we investigated the role of Knr4 protein in the cells sensitivity towards the toxin. We were able to show that the presence of the N-terminal domain of Knr4 protein, which is required for its correct cellular localization at the bud tip during cell cycle, is essential for the toxin K9 wild-type sensitivity. In addition, a series of deletion mutants from the YKO collection in which the Knr4 cellular localization is also lost display a reduced sensitivity to the K9 toxin. Taken together, these results shed light on the importance of the proper localization of Knr4 protein at sites of intensive cell wall growth for the wild-type cells sensitivity to K9 killer toxin.
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Dates et versions

hal-01553082 , version 1 (07-09-2017)

Identifiants

  • HAL Id : hal-01553082 , version 1
  • PRODINRA : 308200

Citer

Ran Liu, Cécile Formosa-Dague, Adilia Dagkessamanskaia, Etienne Dague, Jean Marie François, et al.. Combining atomic force microscopy and genetics to investigate the role of KNR4 in Saccharomyces Cerevisiae sensitivity to K9 killer toxin. Letters in Applied NanoBioScience, 2015, 4 (4), pp.306-315. ⟨hal-01553082⟩
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