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Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion

Cell–cell fusion is central for sexual reproduction, and generally involves gametes of different shapes and sizes. In walled fission yeast Schizosaccharomyces pombe, the fusion of h+ and h− isogametes requires the fusion focus, an actin structure that concentrates glucanase-containing vesicles for c...

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Autores principales: Muriel, Olivia, Michon, Laetitia, Kukulski, Wanda, Martin, Sophie G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Rockefeller University Press 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8366684/
https://www.ncbi.nlm.nih.gov/pubmed/34382996
http://dx.doi.org/10.1083/jcb.202103142
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author Muriel, Olivia
Michon, Laetitia
Kukulski, Wanda
Martin, Sophie G.
author_facet Muriel, Olivia
Michon, Laetitia
Kukulski, Wanda
Martin, Sophie G.
author_sort Muriel, Olivia
collection PubMed
description Cell–cell fusion is central for sexual reproduction, and generally involves gametes of different shapes and sizes. In walled fission yeast Schizosaccharomyces pombe, the fusion of h+ and h− isogametes requires the fusion focus, an actin structure that concentrates glucanase-containing vesicles for cell wall digestion. Here, we present a quantitative correlative light and electron microscopy (CLEM) tomographic dataset of the fusion site, which reveals the fusion focus ultrastructure. Unexpectedly, gametes show marked asymmetries: a taut, convex plasma membrane of h− cells progressively protrudes into a more slack, wavy plasma membrane of h+ cells. Asymmetries are relaxed upon fusion, with observations of ramified fusion pores. h+ cells have a higher exo-/endocytosis ratio than h− cells, and local reduction in exocytosis strongly diminishes membrane waviness. Reciprocally, turgor pressure reduction specifically in h− cells impedes their protrusions into h+ cells and delays cell fusion. We hypothesize that asymmetric membrane conformations, due to differential turgor pressure and exocytosis/endocytosis ratios between mating types, favor cell–cell fusion.
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spelling pubmed-83666842022-04-04 Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion Muriel, Olivia Michon, Laetitia Kukulski, Wanda Martin, Sophie G. J Cell Biol Article Cell–cell fusion is central for sexual reproduction, and generally involves gametes of different shapes and sizes. In walled fission yeast Schizosaccharomyces pombe, the fusion of h+ and h− isogametes requires the fusion focus, an actin structure that concentrates glucanase-containing vesicles for cell wall digestion. Here, we present a quantitative correlative light and electron microscopy (CLEM) tomographic dataset of the fusion site, which reveals the fusion focus ultrastructure. Unexpectedly, gametes show marked asymmetries: a taut, convex plasma membrane of h− cells progressively protrudes into a more slack, wavy plasma membrane of h+ cells. Asymmetries are relaxed upon fusion, with observations of ramified fusion pores. h+ cells have a higher exo-/endocytosis ratio than h− cells, and local reduction in exocytosis strongly diminishes membrane waviness. Reciprocally, turgor pressure reduction specifically in h− cells impedes their protrusions into h+ cells and delays cell fusion. We hypothesize that asymmetric membrane conformations, due to differential turgor pressure and exocytosis/endocytosis ratios between mating types, favor cell–cell fusion. Rockefeller University Press 2021-08-12 /pmc/articles/PMC8366684/ /pubmed/34382996 http://dx.doi.org/10.1083/jcb.202103142 Text en © 2021 Muriel et al. http://www.rupress.org/terms/https://creativecommons.org/licenses/by-nc-sa/4.0/This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms/). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Article
Muriel, Olivia
Michon, Laetitia
Kukulski, Wanda
Martin, Sophie G.
Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion
title Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion
title_full Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion
title_fullStr Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion
title_full_unstemmed Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion
title_short Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion
title_sort ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8366684/
https://www.ncbi.nlm.nih.gov/pubmed/34382996
http://dx.doi.org/10.1083/jcb.202103142
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