CELL JUNCTIONS

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CELL JUNCTIONS : 

CELL JUNCTIONS

Cell junctions are provided by cell adhesion molecules: 

Cell junctions are provided by cell adhesion molecules Cell Adhesion Molecules (CAMs) are proteins located on the cell surface involved with the binding with other cells or with the extracellular matrix (ECM) in the process called “cell adhesion”. Essentially, cell adhesion molecules help cells stick to each other and to their surroundings.

These proteins are typically transmembrane receptors and are composed of three domains: : 

These proteins are typically transmembrane receptors and are composed of three domains: an intracellular domain that interacts with the cytoskeleton, a transmembrane domain an extracellular domain that interacts either with other CAMs of the same kind ( homophilic binding) or with other CAMs or the extracellular matrix ( heterophilic binding).

ADHESIVE JUNCTION “buttons or zipper” between 2 cells Consist of dense glycoprotein bodies inside cells (plaques): 

ADHESIVE JUNCTION “ buttons or zipper” between 2 cells Consist of dense glycoprotein bodies inside cells (plaques ) DESMOSOME – between 2 cells. Proteins called cadherins between 2 plaques - spot-desmosomes Band-desmosomes Can be “ adherens junction” actine + cadherine . Less strong than desmosome HEMIDESMOSOMES – between cell and basal membrane. Proteins called Integrines of cell anchored to the matrix.

TIGHT JUNCTION : 

TIGHT JUNCTION - 2 cells fuse together by occludins - Create impermeable barrier in kidneys, brain, intestines

JUNCTION COMPLEX: 

JUNCTION COMPLEX Tight junction + adhesive junction

GAP JUNCTION: 

GAP JUNCTION - Cytoplasmic bridge between cells for passing chemical and electrical signals Connexines – cylindrical proteins - Mostly in heart and nerves, but can be found in liver, pancreas, ovary, thyroid glands

ZONULA OCCLUDENS : 

ZONULA OCCLUDENS Zone where row of occludines create barrier

ZONULA ADHERENS : 

ZONULA ADHERENS Zone of belt-desmosome or Adherens junction

PowerPoint Presentation: 

MACULA ADHERENS -DESMOSOME