Journal of Glycobiology
Open Access

Cell Adhesion Quality Articles

To form an anchoring junction, cells must first adhere. A bulky cytoskeletal apparatus must then be assembled around the molecules that directly mediate the adhesion. The result is a well-defined structure—a desmosome, a hemidesmosome, a focal adhesion, or an adherens junction—that is easily identified in the electron microscope. Indeed, electron microscopy provided the basis for the original classification of cell junctions. In the early stages of cell junction development, however, before the cytoskeletal apparatus has assembled, cells often adhere to one another without clearly displaying these characteristic structures; in the electron microscope, one may simply see two plasma membranes separated by a small gap of a definite width. Functional tests show, nevertheless, that the two cells are stuck to each other, and biochemical analysis can reveal the molecules responsible for the adhesion.The study of cell-cell junctions and the study of cell-cell adhesion were once quite distinct endeavors, originating from two different experimental approaches—junctions through electron microscopic description, and adhesion through functional tests and biochemistry.