|
|
|
|
|
|
|
||
* Department of Biology, University of Toledo, Toledo, Ohio 43606; and Squamous epithelial cells have both adherens junctions and desmosomes. The ability of these
cells to organize the desmosomal proteins into a functional structure depends upon their ability first to organize an adherens junction. Since the adherens junction and the desmosome are separate structures with different molecular make up, it is not immediately obvious
why formation of an adherens junction is a prerequisite
for the formation of a desmosome. The adherens junction is composed of a transmembrane classical cadherin (E-cadherin and/or P-cadherin in squamous epithelial
cells) linked to either Department of Dermatology, University of
Pennsylvania, Philadelphia, Pennsylvania 19104
-catenin or plakoglobin, which is
linked to 
-catenin, which is linked to the actin cytoskeleton. The desmosome is composed of transmembrane proteins of the broad cadherin family (desmogleins and desmocollins) that are linked to the
intermediate filament cytoskeleton, presumably
through plakoglobin and desmoplakin. To begin to
study the role of adherens junctions in the assembly of
desmosomes, we produced an epithelial cell line that
does not express classical cadherins and hence is unable
to organize desmosomes, even though it retains the requisite desmosomal components. Transfection of E-cadherin and/or P-cadherin into this cell line did not restore the ability to organize desmosomes; however,
overexpression of plakoglobin, along with E-cadherin,
did permit desmosome organization. These data suggest that plakoglobin, which is the only known common component to both adherens junctions and desmosomes, must be linked to E-cadherin in the adherens
junction before the cell can begin to assemble desmosomal components at regions of cell-cell contact. Although adherens junctions can form in the absence of
plakoglobin, making use only of -catenin, such junctions cannot support the formation of desmosomes.
Thus, we speculate that plakoglobin plays a signaling
role in desmosome organization.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
