Loading in 2 Seconds...
Loading in 2 Seconds...
Influence of extracellular Ca 2+ on cell shape and tensegrity. Background . Results.
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
In all eukaryotic cells, the extracellular concentration of calcium ions Ca2+ is tightly controlled by hormones like PTH and calcitonin and vitamin-D. Finely, tuned changes in Ca2+modulate a variety of intracellular functions, and disruption of Ca2+ handling leads to cell death (Rosario Rizzuto1 & TullioPozzan, Nature Genetics, 2003).
Tensegrity system is a building principle of prestressed structures that stabilize their shape by continuous tension or `tensional integrity' rather than by continuous compression.
The “cellular tensegrity model” proposes that the whole cell is a prestressedtensegrity structure. In the model, tensional forces are borne by cytoskeletal microfilaments and intermediate filaments, and these forces are balanced by compression of microtubule struts structural elements , all being interconnected. Most notably, these forces are resisted by internal adhesion proteins and extracellular matrix (ECM) (Donald E. Ingber , Cell Science, 2003). Also recent works show that mechanical distortion of cells and the cytoskeleton through cell surface integrin receptors can profoundly affect cell behavior. Hence, the cytoskeleton also orients much of the cell's metabolic and signal transduction machinery leading to molecular changes. Most important, the binding of integrins to their ligands on ECM and cadherins that link cells to the cytoskeleton, also mediating transmembrane mechanical coupling between neighbor cells, strongly depend on extracellular divalent cations , Ca2+ or Mg2+ (Molecular Biology of the Cell,2002).
Ingber proposed that many diseases are the result of abrupt changes in the normal tensile forces of cells influenced by their environment. It is therefore tempting to find a correlation between extracellular Ca2+ and cellular tension (tensegrity). Recently, a mathematical model expressing such relationship between tensegrity and extracellular calcium was established by our group.
Students: EyalDekel and Inna Nakhimova, Tel-Aviv University, department of Bio-Medical Engineering Supervisor: Prof. ItzhakBinderman, Tel-Aviv University, department of Bio-Medical Engineering
Both pictures perform cells in 0.75mM Ca2+