In epithelia, intercellular adhesion is maintained by adherens
junctions and desmosomes. We are studying adhesion via
adherens junctions. The primary molecule responsible for
intercellular adhesion is E-cadherin (blue ellipses).
This picture outlines trafficking of E-cadherin to and from
the cell surface.
After E-cadherin is synthesized at the endoplasmic reticulum it
binds to either b-
catenin (also called plakoglobin) and then transports via the
secretory pathway to the cell surface (plasma membrane).
At some point p120 catenin is also added to the complex.
When E-cadherins from adjacent cells bind to each other
(binding is calcium dependent) then an adherens junction is
established. During apoptosis trafficking of E-cadherin
to the cell surface is lost. Therefore, as E-cadherin is
turned-over cells detach from one another.