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Anatomy

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Histology

Question
23 out of 59
 

Which glycoprotein functions to bind cells at a hemidesmosome to an underlying basal lamina (LQ)



A Heparin sulfate
B Fibronectin

C Integrin
D Tenascin

Ans. C

Integrin

1. Cell Adhesion Molecules (CAMs) are proteins located on the cell surface involved with the binding with other cells or with the extracellular matrix (ECM) in the process called cell adhesion.

2. These proteins are typically transmembrane receptors

3. Most of the CAMs belong to 4 protein families: Ig (immunoglobulin) superfamily (IgSF CAMs), the integrins, the cadherins and the selectins.

Selectins

1. The selectins are calcium-dependent CAMs. The three family members are E-selectin (endothelial), L-selectin (leukocyte) and P-selectin (platelet).

Cadherins

1. Cadherins are a class of transmembrane proteins. They play important roles in cell adhesion whereby they ensure cells within tissues are bound together. They are dependent on calcium (Ca2+) ions to function, hence their name.

2. The most important members of this family are E-cadherins (epithelial), P-cadherins (placental) and N-cadherins (neural).

3. In epithelial cells, E-cadherin-containing cell-to-cell junctions are often adjacent to actin-containing filaments of the cytoskeleton.

4. Loss of E-cadherin function or expression has been implicated in cancer progression and metastasis.

Integrins

1. An integrin, or integrin receptor, is an integral membrane protein in the plasma membrane of cells.

2. Two main functions of integrins are:

a. Attachment of the cell to the ECM.

b. Signal transduction from the ECM to the cell.

3. They are also involved in binding of viruses to the cells

4. One of their most important functions is their role in cell migration. The movement of any body requires its feet to advance over the substratum. In this sense, integrins are the feet of the cell.

Pemphigus is a group of conditions that are characterized by the formation of blisters within the epidermis of both skin and mucous membranes. It is characterised by intra-epidermal separation of keratinocytes forming a split between the upper and lower portions of the epidermis due to damaged desmosomes

5. In comparison, bullous pemphigoid is characterised by blister formation at the level of the basement membrane and not within the epidermis. It occurs in damage to hemidesmosomes, which bind the epithelium to the basal lamina using integrin as the cell adhesion molecules

Histology Flashcard List

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