Membrane Cytoskeleton Interactions, A Model System : The Intestinal Microvilli
Epithelial cells display a striking structural and functional polarity. Inside the cell, the arrangement of different organelles is highly ordered and their function is coordinated. For example, secretory proteins, plasma membrane proteins and at least some of the lysosomal enzymes are assembled in the rough endoplasmic reticulum and then pass through the Golgi complex before reaching their final destination inside or outside the cell. In addition, the plasma membrane contains at least two specialized domains: the apical face which is involved in absorption or secretory processes and is covered with microvilli, whereas the basolateral faces are involved in exchanges with the blood front and are generally free of microvilli. Each domain possesses a characteristic set of proteins specific for their particular function. These two surfaces are separated from one another by junctional complexes that limit the penetration of macromolecules into the intercellular spaces. The tight junction is also throught to prevent lateral diffusion of proteins from one surface domain to the other.
KeywordsSarcoplasmic Reticulum Brush Border Actin Binding Protein Core Filament Intestinal Microvillus
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