Desmosome and Its Function
ASSIGNMENT | DESMOSOME STRUCTURE & ITS FUNCTIONS |
Bricks in a building must be stuck together and also tied somehow to the foundation. Similarly, cells within tissues and organs must be anchored to one another and attached to components of the extracellular matrix. Cells have developed several types of junctional complexes to serve these functions, and in each case, anchoring proteins extend through the plasma membrane to link cytoskeletal proteins in one cell to cytoskeletal proteins in neighboring cells as well as to proteins in the extracellular matrix.
ANCHORING JUNCTIONS Three types of anchoring junctions are observed, and differ from one another in the cytoskeletal protein anchor as well as the transmembrane linker protein that extends through the membrane:
| JUNCTION | CYTOSKELETAL
ANCHOR | TRANSMEMBRANE
LINKER | TIES CELL TO | 1 | DESMOSOMES | INTERMEDIATE FILAMENTS | CADHERIN | OTHER CELLS | 2 | HEMIDESMOSOMES | INTERMEDIATE FILAMENTS | INTEGRINS | EC MATRIX | 3 | ADHERENS JUNCTIONS | ACTIN FILAMENTS | CADHERIN
INTEGRINS | OTHER CELLS
EC MATRIX |
HISTORICAL BACKGROUND The desmosome was first observed in the spinous layer of epidermis by the Italian pathologist Giulio Bizzozero (1846–1901). Bizzozero 's observations of these small dense nodules, subsequently named “nodes of Bizzozero,” led him to the insightful interpretation of these structures as adhesive cell–cell contact points. The term desmosome was later coined by Josef Schaffer in 1920 and is derived from the Greek words “desmo,” meaning bond or fastening, and “soma,” meaning body .
The introduction of electron microscopy yielded a series of advances by Porter, Odland, and Kelly in the 1950s and 1960s, which revealed
Bricks in a building must be stuck together and also tied somehow to the foundation. Similarly, cells within tissues and organs must be anchored to one another and attached to components of the extracellular matrix. Cells have developed several types of junctional complexes to serve these functions, and in each case, anchoring proteins extend through the plasma membrane to link cytoskeletal proteins in one cell to cytoskeletal proteins in neighboring cells as well as to proteins in the extracellular matrix.
ANCHORING JUNCTIONS Three types of anchoring junctions are observed, and differ from one another in the cytoskeletal protein anchor as well as the transmembrane linker protein that extends through the membrane:
| JUNCTION | CYTOSKELETAL
ANCHOR | TRANSMEMBRANE
LINKER | TIES CELL TO | 1 | DESMOSOMES | INTERMEDIATE FILAMENTS | CADHERIN | OTHER CELLS | 2 | HEMIDESMOSOMES | INTERMEDIATE FILAMENTS | INTEGRINS | EC MATRIX | 3 | ADHERENS JUNCTIONS | ACTIN FILAMENTS | CADHERIN
INTEGRINS | OTHER CELLS
EC MATRIX |
HISTORICAL BACKGROUND The desmosome was first observed in the spinous layer of epidermis by the Italian pathologist Giulio Bizzozero (1846–1901). Bizzozero 's observations of these small dense nodules, subsequently named “nodes of Bizzozero,” led him to the insightful interpretation of these structures as adhesive cell–cell contact points. The term desmosome was later coined by Josef Schaffer in 1920 and is derived from the Greek words “desmo,” meaning bond or fastening, and “soma,” meaning body .
The introduction of electron microscopy yielded a series of advances by Porter, Odland, and Kelly in the 1950s and 1960s, which revealed
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