Desmosomes and hemidesmosomes are cell junctions that connect adjacent cells or attach cells to the extracellular matrix. Desmosomes link the intermediate filaments of neighboring cells, forming strong bonds especially in tissues under mechanical stress like skin. They are composed of transmembrane proteins, plaque proteins, and intermediate filaments. Hemidesmosomes attach basal epithelial cells to the basement membrane. Loss of desmosome function can cause skin and mucous membrane fragility disorders like pemphigus.

1. DESMOSOMES &
HEMIDESMOSOMES
Submitted by,
AJAY DOMINIC.V
ROLL NO:251

2.  The plasma membranes of adjacent cells are usually
separated by a uniform intercellular space of about 100-
200 A.
 But at certain places the plasma membranes of adjacent
cells may come too close to each other the term CELL
JUNCTION.
 It refers to specialisations in the plasma membrane
formed at sites where two cells make contact.
 Cell junctions are different types : desmosomes, gap-
junctions, tight junctions & plasmodesmata….

3. DESMOSOMES(Adherent junctions)
 Desmosomes are essential adhesion structures in
most epithelia that link the intermediate filament
network of one cell to its neighbour, thereby
forming a strong bond.
 They are particularly numerous in tissues that are
subjected to mechanical stress, such as the skin
& uterine cervix.

4. Structure of Desmosomes

5. Desmosome consists of three component
 The Transmembrane molecules
 The plaque molecules or cytoplasmic adaptor
protein
 Intermediate filament
 Extracellularly , desmosomes are separated by a
25-30 nm space.

6. The interaction of the transmembrane
proteins with those from the adjacent cell
results in a dense line in the middle of the
intercellular space.

7. Function of Desmosomes
 Desmosomes create a transcellular network
throughout a tissue that resist forces of
mechanical stress. Hence found in
stratified squamous epithelia and
myocardium subjected to constant stress.

8. ASSOCIATED PATHOLOGY
 Desmosomes are adhesive intercellular junctions
prominent in the oral epithelium, skin & heart. Loss of
desmosome function is associated with severe congenital
& acquired disorders characterized by tissue fragility.
 Diseases associated are-
 Pemphigus
 Drug-induced pemphigus

9. PEMPHIGUS
 Mutations in genes encoding desmosomal
components & autoantibodies directed
against the desmosomal cadherins lead to
severe epidermal blistering disorders
termed pemphigus.

10. HEMIDESMOSOMES
 Hemidesmosomes are specialized junctional
complexes that contribute to the
attachment of epithelial cell to the
underlying basement membrane in
stratified & other complex epithelia.

12.  Hemidesmosomes are very small stud or rivet like
structures on the inner basal surface of keratinocytes in
the epidermis of skin.
 While desmosomes link two cells together,
hemidesmosomes attach one cell to the extracellular
matrix.
 Hemidesmosomes use integrin cell adhesion proteins.
 Hemidesmosomes are asymmetrical & are found in
epithelial cells connecting the basal face to other cells.
 Function : maintenance of tissue structure.

13. DISORDERS
 AUTOIMMUNE DISEASES
 PEMPHIGOID
Term used to indicate a blistering disease in which epithelial separation
takes place at the level of the basement membrane.

14. Thank you