Cell cortex

The cortex mainly functions to produce tension under the cell membrane, allowing the cell to change shape. Thus, the cell cortex serves to protect the microtubule spindle from external mechanical disruption during mitosis. When external forces are applied at sufficiently large rate and magnitude to a mitotic cell, loss of cortical F-actin homogeneity occurs leading to herniation of blebs and a temporary loss of the ability to protect the mitotic spindle. Genetic studies have shown that the cell cortex in mitosis is regulated by diverse genes such as Rhoa, WDR1, ERM proteins, Ect2, Pbl, Cdc42, , Par6, DJ-1 and FAM134A. In cytokinesis the cell cortex plays a central role by producing a myosin-rich contractile ring to constrict the dividing cell into two daughter cells. Cell cortex contractility is key for amoeboidal type cell migration characteristic of many cancer cell metastasis events. In addition to cell cortex also plays essential roles in the formation of tissues, organs and organisms. By pulling on adhesion complexes, the cortex promotes the expansion of contacts with other cells or with the extracellular matrix. Notably, during early mammalian development, the cortex pulls cells together to drive compaction and the formation of the morula. Also, differences in cortical tension drives the sorting of the inner cell mass and trophectoderm progenitors during the formation of the morula, the sorting of germ layer progenitors during zebrafish gastrulation, the invagination of the mesoderm and the elongation of the germ band elongation during drosophila gastrulation. == Research ==