The extracellular matrix

The extracellular matrix - of chemical and mechanical...

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The extracellular matrix (ECM) of animal cells functions in support, adhesion, movement, and regulation. Though lacking cell walls, animal cells do have an elaborate  extracellular matrix (ECM). The primary constituents of the extracellular matrix are glycoproteins, especially  collagen fibers, embedded in a network of glycoprotein  proteoglycans . In many cells,  fibronectins  in the ECM connect to  integrins,  intrinsic membrane proteins  that span the membrane and bind on their cytoplasmic side to proteins attached to  microfilaments of the cytoskeleton. The interconnections from the ECM to the cytoskeleton via the fibronectin-integrin link  permit the integration of changes inside and outside the cell. The ECM can regulate cell behavior. Embryonic cells migrate along specific pathways by matching the orientation of their  microfilaments to the “grain” of fibers in the extracellular matrix. The extracellular matrix can influence the activity of genes in the nucleus via a combination 
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Unformatted text preview: of chemical and mechanical signaling pathways. This may coordinate the behavior of all the cells within a tissue. Intercellular junctions help integrate cells into higher levels of structure and function. Neighboring cells in tissues, organs, or organ systems often adhere, interact, and communicate through direct physical contact. Plant cells are perforated with plasmodesmata, channels allowing cytosol to pass between cells. Water and small solutes can pass freely from cell to cell. In certain circumstances, proteins and RNA can be exchanged. Animals have 3 main types of intercellular links: tight junctions, desmosomes, and gap junctions. In tight junctions, membranes of adjacent cells are fused, forming continuous belts around cells. This prevents leakage of extracellular fluid....
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This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.

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