CELL POLARITY

cell polarity: translation

(1) In epithelial cells the differentiation of apical and basal specializations. In many epithelia the apical and basolateral regions of plasma membrane differ in lipid and protein composition, and are isolated from one another by tight junctions. The apical membrane may, for example, be the only region where secretory vesicles fuse, or have a particular ionic pumping system.

(2) A motile cell must have some internal polarity in order to move in one direction at a time: a region in which protrusion will occur (the front) must be defined. Locomotory polarity may be associated with the pericentriolar microtubule organizing centre, and can be perturbed by drugs that interfere with microtubule dynamics.