Nidi for cell aggregation
Influence tissue states (layering)
Mediate selective cell-cell adhesion
Regulate embryologic cell sorting
Switches specific cadherin expression
Segregates embryological layers
Image from Farquhar and Palade below, and enlargement
It looks to me like the extracellular domains of the desmosomal cadherins (model found from some other publication obviously) fits well below the plasmalemma of the two apposed cells. This puts the transmembrane and intracellular domains of the cadherins here as a huge portion of the remaining molecule to span from the top and bottom of the punctuated extracellular space (this doesn’t include the dotted central density of the extracellular space generally called EC1) quite a ways from the plasmalemma. I am waiting to find a WHOLE molecular model of desmocollin 2 or desmoglein so i can visually “fit” those molecules THROUGH the plasmalemma on both sides of the cell-cell junction. The red circles, likely the densities at regular intervals of the connection of the intracellular portions of desmocollins/desmogleins with the plakoglobin and plakophilin? There are some very nice tomographic images and studies of desmosomes, but they seem to fit the TEM of the extracellular molecules pretty well (not perfectly) but dont manage to show the transmembrane and intracellular portions of the cadherins with any clarity, in my opinion. And I cant find any molecular images of the whole cadherins (all 3 domains).