Here is an article by Gallicano et al, which I think has some interesting ultrastructure. They created a desmoplakin ko, and followed some of the changes in structure, but I think there might be more changes than they allude to. I took two of their micrographs and measured (using their own nm markers) the height of the wt desmosomal plaque, the extracellular space and the ring dimension of the annulus… and i think there is an effect of the lack of desmoplakin on how narrow the extracellular space is, and also there is an absence of the very electron lucent layer just above the plasmalemma of the desmosome (just immediately intracellular, almost one could say, beneath the plakophilin and plakoglobin). Since the position of both those proteins as well as the intracellular portion of desmocollin and desmoglein are linked directly and/or indirectly, then it would be reasonable to think that the extracellular dimension (as well as the intracellular thickness of the outer and inner plaques as well as the whole dimension of the desmosome might change.
Extracellular dimension of the ko desmosome, 19nm (according to their own micron marker), and the extracellular dimension for the wt desmosome is ,pre ;ole 16nm. In both the wt case, the extracellular space between those adjacent cells is wider than what is found actually at the desmosome. This is not that apparent for the ko. Similarly the annulus protein seems to be longer (wt=26nm ko=35nm)(though tangential section could easily account for this). Just interesting to see how subtle changes in the TEM are present. Red and black vertical and horizontal bars=100nm. Green bar=extracellular space at desmosome. Pink bar=desmosomal annulus. Loss of IFs in image to the right, reflecting lack of desmoplakin connections with intermediate filaments, and I think too changing the position, orientation, and closeness of the four+ other proteins comprising the desmosome. (mouse). Looking again at these micrographs, they are most assuredly NOT the same magnification as was indicated on their micrographs.
