MOLBIOL 3B03 Lecture Notes - Lecture 3: Focal Adhesion, Cell Adhesion, Tight Junction
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5 Jan 2017
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The plasma membranes of polarized cells are organized into at least two discreet regions: Lateral (side) this is similar in composition to the basal and is often called basolateral. Types of junctions to connect cells and maintain polarity: Anchoring junctions have cadherin and other anchoring proteins. Allow small molecules to pass directly from cell to cell. Flow of cytosol, chemical signals, nutrients, ions and water soluble molecules. Channel forming proteins called connexion (vertebrates) and innexins (invertebrates) Different sets of connexions are expressed in different cells. Channels formed by connexins are called connexons. Channels allow small inorganic molecules and other small water-soluble molecules to pass directly from one cell to other. Permeability of gap junctions can be regulated. Ex: gap junctions are sealed in response to dopamine. Seal gap between cells no water movement. Cell-cell interactions are mediated through the extracellular domains of occludin, These are located on the plasma membrane. Calcium ion plays a role in tight junction function.