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bioRxiv · 10.1101/2021.10.15.464498

Cofilin regulates actin network homeostasis and microvilli length in mouse oocytes

Bourdais, A.·Dehapiot, B.·Halet, G.
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Abstract

How multiple actin networks coexist in a common cytoplasm, while competing for a shared pool of monomers, is still an ongoing question. This is exemplified by meiotic maturation in the mouse oocyte, which relies on the dynamic remodeling of distinct cortical and cytoplasmic F-actin networks. Here we show that the conserved actin-depolymerizing factor cofilin is activated in a switch-like manner at meiosis resumption from prophase arrest. Interfering with cofilin activation during maturation resulted in widespread microvilli elongation, while cytoplasmic F-actin was depleted, leading to defects in spindle migration and polar body extrusion. In contrast, cofilin inactivation in metaphase II-arrested oocytes resulted in a shutdown of F-actin dynamics, along with a dramatic overgrowth of the polarized actin cap. However, inhibition of the Arp2/3 complex to promote actin cap disassembly elicited ectopic microvilli outgrowth in the polarized cortex. These data establish cofilin as a key player in actin network homeostasis in oocytes, and reveal that microvilli can act as a sink for monomers upon disassembly of a competing network.

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Bourdais, A., Dehapiot, B., Halet, G.. 2021-10-15. Cofilin regulates actin network homeostasis and microvilli length in mouse oocytes. https://doi.org/10.1101/2021.10.15.464498

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