BIOL 1215 Lecture Notes - Adherens Junction, Tight Junction, Cadherin
Document Summary
Tight junctions, adheren junctions, desmosomes, hemidesmosomes and gap. Junctions: tight junctions- consist of web-like strands of transmembrane proteins that fuse outer surfaces of adjacent plasma membrane together to seal off passageways between adjacent cells. Each cadherin inserts into plaque from opposite side of plasma membrane, partially crosses intercellular space (space between cells), and connects to cadherins of adjacent cells. In epithelial cells, adherens junctions form extensive zones called adhesion belts because they encircle cells. Adhesion junctions help epithelial surfaces resist separation during contractile activities (food moves through intestines: desmosomes- Contain plaque and cadherins that extends into the intercellular space between adjacent membranes and attach cells to one another. Plaque attaches to elements of cytoskeleton called intermediate filaments that consist of keratin (protein). Intermediate filaments extend from desmosomes on one side of cell across the cytosol to desmosomes on opposite side of cell. Structural arrangement contributes to stability of cells and tissues.
