Hemidesmosomes

Definition: Specialized adhesive structure at the basal surface of epithelial cells that functions to attach  the cells to the underlying basement membrane. The hemidesmosome contains a dense plaque on the inner surface of the plasma membrane, with keratin containing filaments coursing out into the cytoplasm

Hemidesmosome anchor epithelial cells to a basement membrane

• Similar to desmosomes but totally different molecular structure
• Cell matrix adhesions –attach cells to basal lamina

Molecular Structure of Hemidesmosomes

• Composed of integrins (outside) that bind to type XVII collagen and laminin -5
• Cytosolic side consists of a plague composed of adaptor proteins (plectin) attaching integrins to keratin filaments.