Cell Junctions Flashcards
Tight junctions
Hold cells and prevent movement or water and of water-soluble molecule between cells.
Cell junctions
Multiprotein complexes, provide cell-cell and cell-ECM contact.
Proteins forming tight junctions
Occludin
Clausin
Junctional adhesion molecules
Tricellulins
Adherens junctions
Provide strong mechanical attachment between adjacent cells.
Example: in cardiac muscle cells while contacting
Proteins forming adherens junctions
Cadherins (transmembrane)
Catenins (connected to actin filaments)
Desmosomes
Thickened patches in the cell membrane region between two cells.
Proteins forming desmosomes
Keratine
Desmoplakin
Desmin filaments (increase rigidity of tissues)
Spot desmosome
Two buttonlike adhesion plaques
Bind cells together
Anchors for fibers in cytoskeleton
Desmosomes and cytoskeleton
Desmosomes provide anchor points for the components of the cytoskeleton, such as the keratin intermediate filaments.
Hemidesmosomes
Bind the base of the cell to the underlying basement membrane by linking to the cell’s intermediate filament network.
Proteins forming hemidesmosomes
Integrins
Gap junctions
Specialized channels that allow direct cytoplasmic communication among cells thus the passage of small molecules.
Example: heart cells (responsible for coordination)
Proteins forming gap junctions
Connexins
How to gap junctions get formed?
Six of the connexin proteins come together, and then interact with another hexamer in the neighboring cell, resulting in the formation of a channel.
Gap junctions (function)
Help coordinate the activities of adjacent cells.
Allow direct cytoplasmic communication, letting small molecules pass through the channels whose opening or closing can be controlled locally in the cell.