(A) Desmosomes. The integrity of epidermal cell cohesion is largely dependent on desmosomes, plaque-like intercellular adhesion structures that connect transmembranous adhesion molecules such as the desmogleins and desmocollins with keratins of the cytoskeleton through interaction with intracellular components of the desmosomal plaque such as desmoplakin, plakoglobin, plakophilin, envoplakin, and periplakin. In addition to Dsg3 and Dsg1, which are autoantigens in pemphigus, all the other aforementioned components of desmosomes have been identified as autoantigens of different clinical variants of pemphigus. (B) Hemidesmosomes and components of the dermoepidermal basement membrane. Basal keratinocytes adhere to the basement membrane zone by the interaction of cytoplasmic and transmembranous components of hemidesmosomes, such as BP230 and BP180 and α₆β₄ integrin, with ligands such as laminin 5 located in the lamina lucida and lamina densa of the dermoepidermal basement membrane zone. The intracellular hemidesmosomal components BP230 and plectin are linked to keratins of the cytoskeleton and interact with the cytoplasmic domains of BP180 and α₆β₄ integrin, which in turn interact with laminin 5 via their ectodomains. Type VII collagen is the major component of anchoring fibrils, which link the basement membrane to interstitial dermal collagen fibers by direct interaction with laminin 5 in the lamina densa of the basement membrane. Figure modified from ref. 58.