RT Journal Article
SR Electronic
T1 Membrane tension spatially organizes lysosomal exocytosis
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.04.22.489160
DO 10.1101/2022.04.22.489160
A1 Hugo Lachuer
A1 Laurent Le
A1 Sandrine Lévêque-Fort
A1 Bruno Goud
A1 Kristine Schauer
YR 2022
UL http://biorxiv.org/content/early/2022/04/22/2022.04.22.489160.abstract
AB Lysosomal exocytosis is involved in many key cellular processes but its spatio-temporal regulation is poorly known. Using total internal reflection fluorescence microscopy (TIRFM) and spatial statistics, we observed that lysosomal exocytosis is not random at the adhesive part of the plasma membrane of RPE1 cells but clustered at different scales. Although the rate of exocytosis is regulated by the actin cytoskeleton, neither interfering with actin or microtubule dynamics by drug treatments alters its spatial organization. Exocytosis events partially co-appear at focal adhesions (FAs) and their clustering is reduced upon removal of FAs. Changes in membrane tension following a hypo-osmotic shock or treatment with methyl-β-cyclodextrin was found to increase clustering. To investigate the link between FAs and membrane tension, cells were cultured on adhesive ring-shaped micropatterns, which allows to control the spatial organization of FAs. By using a combination of TIRFM and fluorescence lifetime imaging microscopy (FLIM) microscopy, we revealed the existence of a radial gradient in membrane tension. By changing the diameter of micropatterned substrates, we further showed that this gradient as well as the extent of exocytosis clustering can be controlled. Together, our data indicate that the spatial clustering of lysosomal exocytosis relies on membrane tension patterning controlled by the spatial organization of FAs.Competing Interest StatementThe authors have declared no competing interest.