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bioRxiv · 10.1101/2020.03.11.986935

Binding dynamics of α-actinin-4 in dependence of actin cortex tension

Hosseini, K.·Sbosny, L.·Poser, I.·Fischer-Friedrich, E.
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Abstract

Mechano-sensation of cells is an important prerequisite for cellular function, e.g. in the context of cell migration, tissue organisation and morphogenesis. An important mechano-chemical-transducer is the actin cytoskeleton. In fact, previous studies have shown that actin cross-linkers, such as -actinin-4, exhibit mechanosensitive properties in its binding dynamics to actin polymers. However, to date, a quantitative analysis of tension-dependent binding dynamics in live cells is lacking. Here, we present a new technique that allows to quantitatively characterize the dependence of cross-linking lifetime of actin cross-linkers on mechanical tension in the actin cortex of live cells. We use an approach that combines parallel plate confinement of round cells, fluorescence recovery after photo-bleaching, and a mathematical mean-field model of cross-linker binding. We apply our approach to the actin cross-linker -actinin-4 and show that the cross-linking time of -actinin-4 homodimers increases approximately twofold within the cellular range of cortical mechanical tension rendering -actinin-4 a catch bond in physiological tension ranges.

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Hosseini, K., Sbosny, L., Poser, I., Fischer-Friedrich, E.. 2020-03-11. Binding dynamics of α-actinin-4 in dependence of actin cortex tension. https://doi.org/10.1101/2020.03.11.986935

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