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bioRxiv · 10.1101/2025.06.30.662253

Front-rear polarity of intracellular signaling uncovered via giant Dictyostelium cells

Hayashida, Y.·Gomibuchi, Y.·Oosawa, C.·Yasunaga, T.·Morimoto, Y. V.
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Abstract

Intracellular signaling dynamics are often obscured by the spatial and temporal limitations of cell size. Here, we developed a method to enlarge Dictyostelium discoideum cells by partial cytokinesis inhibition, generating multinucleated yet functional giant cells. These cells retained chemotactic signaling, polarity, and motility, enabling high-resolution live-cell imaging. Using fluorescent probes for cAMP and Ca2+, we uncovered a directional, front-to-rear propagation of cAMP signaling and a biphasic Ca2+ response coordinated with actin wave dynamics. Grid-based mapping revealed asymmetric cAMP synthesis and decay kinetics, and vesicle localization suggested spatially regulated cAMP secretion. Combining giant cells with super-resolution or electron microscopy allowed detailed visualization of intracellular local structures at high resolution. Our findings demonstrate that intracellular signaling involves self-organized, spatially structured propagation events aligned with cellular polarity. The giant cell platform offers a powerful and generalizable strategy for dissecting the spatiotemporal logic of single-cell signaling.

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Hayashida, Y., Gomibuchi, Y., Oosawa, C., Yasunaga, T., Morimoto, Y. V.. 2025-07-03. Front-rear polarity of intracellular signaling uncovered via giant Dictyostelium cells. https://doi.org/10.1101/2025.06.30.662253

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