Scientific article
Open access

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

Published inThe Journal of cell biology, vol. 220, no. 10, e202103142
Publication date2021-10-04
First online date2021-08-12

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.

Affiliation Not a UNIGE publication
Citation (ISO format)
MURIEL LOPEZ, Olivia et al. Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion. In: The Journal of cell biology, 2021, vol. 220, n° 10, p. e202103142. doi: 10.1083/jcb.202103142
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Article (Published version)
ISSN of the journal0021-9525

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