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Tight junction
- Cell-cell seal that is impermeable.
- Linked by junctional proteins (claudins and occludins).
- Found only in epithelial cells. Eg. Those linig lumen of the gut.
Adherens junction
- Cell-cell junction that can bend.
- Linked by cadherins connecting actin bundle inside cell. Just below tight junctions.
- The Ca in cadherins means it needs calcium in the extracellular medium.
- Eg. Invagination of epithelial cells to form the neural tube.
Desmosome
- Cell-cell junction that gives tensile strength.
- Linked by cadherins connecting to intermediate filaments (keratin) via plaque of anchor proteins.
- Eg. Epidermis of skin.
Hemidesmosome
- Cell-extracellular matrix junction.
- Linked by integrins connecting to intermediate filaments (keratin)
- Eg. Epithelial cells to basal lamina.
Gap junction
- Cell-cell channel that conducts small ions and molecules.
- Linked by connexons.
- Eg. Transmission of electrical signal through heart and smooth muscle cells to synchronize their contraction.
Focal contact
- Cell to surface adhesion that enables cell crawling.
- Adhesion by integrin connecting to cytoskeleton (actin).
- Eg. Crawling of fibroblasts.
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