Structure of Hemidesmosomes and the Epidermal Basement Membrane Zone
Hemidesmosomes are complex, multiprotein structures that mediate the attachment of epithelial cells to the underlying basement membrane. While providing mechanical attachment, these adhesion units are extremely dynamic. They play a significant role in signaling pathways involved in the various important cell functions, such as differentiation, wound healing, and survival. Structurally, hemidesmosomes contain the following molecules: plectin (over 500 kDa protein), BP230 (230 kDa antigen, also known as BPAG1), integrin α6β4, and BP180 (180 kDa protein, also known as BPAG2 or type XVII collagen, and CD151 (protein of tetraspan superfamily). The epidermal basement membrane zone can be viewed as a thin sheet of matrix underlying the basal epithelial cells. It consists of lamina lucida and lamina densa, mainly containing laminin and type IV collagen networks. Type VII collagen which enters into the composition of semicircular anchoring fibrils provide the attachment to the papillary dermis underneath the lamina densa of the basement membrane. When molecules in hemidesmosomes or in the basement membrane zone become target of autoantibodies, a particular acquired subepidermal autoimmune bullous disease (sAIBD) will develop.
KeywordsHemidesmosome Dermal-epidermal junction Basement membrane zone Autoimmune disease Pemphigoid
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