What is the Difference Between Focal Adhesion and Hemidesmosomes?

Focal adhesions and hemidesmosomes are two types of adhesive interactions that play crucial roles in cell adhesion and the mechanical integrity of the skin. They both extend from the cell rear to the cell front and are involved in keratinocyte migration, which is linked to the wound healing process of re-epithelialization. However, they have distinct functions and compositions:

Focal Adhesions:

• Mediate the adhesion between cells and the extracellular matrix.
• Contain clusters of transmembrane integrin receptors tethered at one end to the extracellular matrix.
• Composed of integrins heterodimers containing alpha and beta subunits, talin, alpha-actinin, vinculin, paxillin, and focal adhesion kinase.

Hemidesmosomes:

• Anchor the epidermal keratin filament cytoskeleton to the extracellular matrix.
• Composed of integrin α6β4, plectin 1a, tetraspanin protein CD151, BPAG1e, and BPAG2.

The key difference between focal adhesion and hemidesmosomes is their function: focal adhesion mediates the adhesion between cells and the extracellular matrix, while hemidesmosomes mediate the anchoring of the epidermal keratin filament cytoskeleton to the extracellular matrix. Although these two adhesive structures are separate entities, they affect each other's distribution and function in a coordinated manner during cell migration.

Comparative Table: Focal Adhesion vs Hemidesmosomes

Focal adhesions and hemidesmosomes are two types of adhesive interactions that play crucial roles in the mechanical integrity of the skin and keratinocyte migration. Here is a table comparing their differences:

Both focal adhesions and hemidesmosomes play important roles in maintaining cell-extracellular matrix connections and cell-cell adhesions, but they have distinct functions and compositions.