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Genes Dev. 2016 Oct 1;30(19):2226-2239.

Spatial focalization of pheromone/MAPK signaling triggers commitment to cell-cell fusion.

Author information

1
Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland.

Abstract

Cell fusion is universal in eukaryotes for fertilization and development, but what signals this process is unknown. Here, we show in Schizosaccharomyces pombe that fusion does not require a dedicated signal but is triggered by spatial focalization of the same pheromone-GPCR (G-protein-coupled receptor)-MAPK signaling cascade that drives earlier mating events. Autocrine cells expressing the receptor for their own pheromone trigger fusion attempts independently of cell-cell contact by concentrating pheromone release at the fusion focus, a dynamic actin aster underlying the secretion of cell wall hydrolases. Pheromone receptor and MAPK cascade are similarly enriched at the fusion focus, concomitant with fusion commitment in wild-type mating pairs. This focalization promotes cell fusion by immobilizing the fusion focus, thus driving local cell wall dissolution. We propose that fusion commitment is imposed by a local increase in MAPK concentration at the fusion focus, driven by a positive feedback between fusion focus formation and focalization of pheromone release and perception.

KEYWORDS:

G-protein-coupled receptor signaling; MAP kinase cascade; cell–cell fusion; fertilization; fission yeast Schizosaccharomyces pombe; formin; pheromone

PMID:
27798845
PMCID:
PMC5088570
DOI:
10.1101/gad.286922.116
[Indexed for MEDLINE]
Free PMC Article

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