Exan 4 2.0 Flashcards
types of cell-cell junctions
gap
tight
adhesive
adhesive junctions
link cells together into tissues
anchor the cytoskeleton to the cell surface
homophilic interactions
cells interact with identical molecules on the surface of the cell to which they adhere
hetrophilic interactions
cell adhesion receptor on one cells interacts with a different molecule on the surface of the cell to which it adheres
two main types of adhesive junctions
adherens junctions
desmosomes
adherens junctions
cadherin-mediated adhesive junctions that interact with actin, predominant in epithelial cells
cadherins are characterized by
a series of structurally similar domains in their extracellular domain
a transmembrane domain
widely varying cytosolic ends
E-cadherins
associate in pairs in the plasma membrane
EC domain have structures that allow them to “zip” together
P-cadherins
“placental” cadherins
desmosomes
button-like points of strong adhesion between adjacent cells in a tissues
desmosome cadherins
desmocollins and desmogleins
lectin
carbohydrate-binding proteins
promote cell-cell adhesions by binding to a specific sugar or sequence of sugars exposed at the outer cell surface
selectins
cell surface glycoproteins that mediate leukocytes with endothelial cells lining blood vessels
tight junctions
specialized structures that serve to seal cells tightly together
claudins
four membrane-spanning domains, thought to interlock to form a tight seal