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The molecular role of cell-cell or cell-extracellular matrix (ECM) contacts on the polarity of epithelial cell has been well characterized. How the spatial distribution of extracellular environment affects cell asymmetry is less studied. Micro-patterned substrates imposing cells to spread on various combinations of adhesive and non-adhesive areas have previously been used to control the orientation of cell division [1] and to demonstrate that cells can generate identical total traction force on the substrate but that individual stress fibers are differently spaced depending on the spatial distribution of its adherence contacts [2]. The reproducible effect on overall cell compartmentalization enabled the quantification of the spatial organization of intracellular compartments. Analyzing the organization of individual cells plated on different micropatterns, one can show that ECM distribution can predictably modulate cell asymmetry and polarity axes (3). The growth of MTs appears modulated by the asymmetric composition of the cortex. The respective positions of the nucleus and the centrosome-Golgi apparatus indicate that the internal cell polarity of these non-migrating cells is in register with the polarity axis of the adhesive environment. Interestingly the cortical asymmetry did not affect the centrosome positioning at the cell centroid. Thus in addition to ECM molecular composition and mechanical properties, ECM geometry could play a key role in developmental processes.
We will argue that the shape of adherent cells, which reflects a tensional force field, undertakes a continuous transformation through the cell division process compatible with the maintenance of tissue integrity during growth or turn over. 1- Thˇry M, Racine V, Pepin A, Piel M, Chen Y, Sibarita JB, Bornens M. The extracellular matrix guides the orientation of the cell division axis. Nat Cell Biol. 2005 Oct;7(10):947-53. Epub 2005 Sep 18. 2- Thˇry M, Pepin A, Dressaire E, Chen Y, Bornens M. Cell distribution of stress fibres in response to the geometry of the adhesive environment. Cell Motil Cytoskeleton. 2006 Mar 20 3- Thˇry M, Racine V, Piel M, Pˇpin A, Dimitrov A, Chen Y, Sibarita JB, Bornens M. in preparation. |
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