Figure 2.
Figure 2. Cell sorting on the basis of cortical tension in development. (A) Illustrations of cell sorting on the basis of surface tension. Differences in cell–cell adhesion between cell types or cortical tension drive the spontaneous segregation of cell types, with those exhibiting the higher surface tension sorting to the center of the tissue. When two cell types with different surface tensions are juxtaposed, one of the tissues engulfs the other, with cells exhibiting higher surface tension sorting internally. (B) The determinants of cortical tension. A cell’s shape and mechanical properties come from its actomyosin cortex, a thin, dense meshwork of cross-linked actin filaments, myosin motors, and actin-binding proteins immediately beneath and tethered to the plasma membrane. This meshwork resists external mechanical deformation and withstands intracellular osmotic pressure, similar to the function of the cell wall in bacteria and plants, but is a much more dynamic structure, turning over in its entirety within 1 min. Cadherin binding in cell–cell adhesions acts to expand the interfaces between cells by reducing the surface tension at sites of contact, directly regulating actomyosin dynamics in adhesions, and mechanically couples cells, stabilizing adhesions against the pulling forces of the cytoskeleton. (C and D) Examples in development where cell sorting on the basis of surface tension function to refine large-scale tissue patterns. (C) In the Drosophila compound eye, signals from the morphogenetic furrow recruit cells into ommatidial precursors. Within each of these facets of the eye, however, differential adhesion and contractility dictate the arrangement of cone cells, whose configurations mimic groups of soap bubbles. (D) In the formation of the somites, paired blocks of mesoderm on either side of the notochord that give rise to the skeleton, skeletal muscles, and parts of the dermis, differences in surface tension are believed to be important in maintaining distinct boundaries. Photograph in C courtesy of Walter Gehring, Biozentrum, University of Basel.

Cell sorting on the basis of cortical tension in development. (A) Illustrations of cell sorting on the basis of surface tension. Differences in cell–cell adhesion between cell types or cortical tension drive the spontaneous segregation of cell types, with those exhibiting the higher surface tension sorting to the center of the tissue. When two cell types with different surface tensions are juxtaposed, one of the tissues engulfs the other, with cells exhibiting higher surface tension sorting internally. (B) The determinants of cortical tension. A cell’s shape and mechanical properties come from its actomyosin cortex, a thin, dense meshwork of cross-linked actin filaments, myosin motors, and actin-binding proteins immediately beneath and tethered to the plasma membrane. This meshwork resists external mechanical deformation and withstands intracellular osmotic pressure, similar to the function of the cell wall in bacteria and plants, but is a much more dynamic structure, turning over in its entirety within 1 min. Cadherin binding in cell–cell adhesions acts to expand the interfaces between cells by reducing the surface tension at sites of contact, directly regulating actomyosin dynamics in adhesions, and mechanically couples cells, stabilizing adhesions against the pulling forces of the cytoskeleton. (C and D) Examples in development where cell sorting on the basis of surface tension function to refine large-scale tissue patterns. (C) In the Drosophila compound eye, signals from the morphogenetic furrow recruit cells into ommatidial precursors. Within each of these facets of the eye, however, differential adhesion and contractility dictate the arrangement of cone cells, whose configurations mimic groups of soap bubbles. (D) In the formation of the somites, paired blocks of mesoderm on either side of the notochord that give rise to the skeleton, skeletal muscles, and parts of the dermis, differences in surface tension are believed to be important in maintaining distinct boundaries. Photograph in C courtesy of Walter Gehring, Biozentrum, University of Basel.

This Feature Is Available To Subscribers Only

or Create an Account

Close Modal
Close Modal