![]() ![]() There are similarities drawn between the actomyosin contractile ring here and the supracellular purse-string in the wound healing mechanism 21, 22, 23. In mammalian cells, these rings were suggested to contract basolaterally and exert an upward force to expel the dying cell and close the gap left behind 18, 19. ![]() Both intrinsic and extrinsic apoptotic pathways can elicit extrusion, and caspase activation is essential to activate the Rho signaling pathway 3, which promotes the formation and contraction of actomyosin rings. The rearrangement of neighboring cells occurs concurrently with apoptotic cell death to expel the dying cell while maintaining intact monolayer 16.Ī well-described coordinated process of cell extrusion, referred to as actin purse-string contraction, is based on the emergence of contractile actomyosin rings, which are formed by the extruding cell itself 17, 18 and by the neighboring cells 18, 19, 20. Cell–cell interactions and cell-matrix adhesions, which are known as mechanosensitive complexes 12, 13, appear as crucial relays to adapt the dynamic stress around the extrusion site across multiple cells 14, 15. It relies on the establishment of mechanical coupling from the neighbors around the extruded cell, mediated by cell cytoskeletal components, and cell adhesion complexes. Cell extrusion leads to cell rearrangements and movements associated to the fluxes of cells and local stresses 9, 10, 11. Cells can be extruded during apoptosis 3, epithelial-mesenchymal transition (EMT) 4, or precancerous cell invasion 5, making cell extrusion a key player in the regulation of homeostatic pressure, i.e., pressure at which cell extrusion compensates cell division 6, morphogenesis 7, and tumor progression 8. During cell extrusion, a cell embedded in an epithelial monolayer loses its apical or basal surface and is subsequently squeezed out of the monolayer by neighboring cells in the basal or luminal side, respectively. ![]() To face these environment challenges, epithelia are dynamics and have to deal constantly with cell renewal and cell extrusions, whose balance is key for epithelia homeostasis 2. This function needs to be maintained, while epithelial cells are constantly challenged by the environment 1. In this work, we provide mechanistic insight into extrusion, an essential epithelial homeostasis process.Įpithelia are cell sheets that act as a covering for most of the internal and external surfaces of the body. A theoretical model integrates these cellular mechanosensitive components to explain why a dual-mode mechanism, which combines lamellipodia protrusion and purse-string contractility, leads to more efficient extrusion than a single-mode mechanism. The co-existence of these two mechanisms is determined by the interplay between the cell-cell and cell-substrate adhesions. The early presence of basal lamellipodia protrusion participated in both basal sealing of the extrusion site and orienting the actomyosin purse-string. Here, we found that during extrusion, a heterogeneous actin network composed of lamellipodia protrusions and discontinuous actomyosin cables, was reorganized in the neighboring cells. However, whether other actin structures could contribute to extrusion and how forces generated by these structures can be integrated are unknown. Current literature supports that epithelia respond to extrusion by forming a supracellular actomyosin purse-string in the neighbors. Yes, this is working awesome.Apoptotic extrusion is crucial in maintaining epithelial homeostasis. Double-click on Sketch-Meaxure.sketchplugin.Download the latest release of the plugin.If you encounter problems managing (toggle hidden/locked, remove, and export) markers created by Sketch Measure, run the menu Plugin - Sketch MeaXure - Help - Rename Old Markers. Customize the order of exported artboards.Export directly with Anima stacks activated.Easily resize markers, without concerns to break them.Fully works with lastest version of Sketch (v66).More stable, not likely to break down after Sketch update.Sketch MeaXure is a re-implemention of Sketch Measure with TypeScript, uses Sketch JavaScript API. ![]()
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