Reference - PMID:34382996 - Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion.
Reference summary
- PubMed ID
- PMID:34382996
- Title
- Ultrastructural plasma membrane asymmetries in tension and curvature promote yeast cell fusion.
- Authors
- Muriel O, Michon L, Kukulski W, Martin SG
- Citation
- J Cell Biol 2021 Oct 04;220(10)
- Publication year
- 2021
- Abstract
- 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.
