Hemidesmosomes (HDs) are highly specialized integrin-mediated epithelial attachment structures that make cells firmly adhere to the extracellular matrix by establishing a link between the underlying basement membrane (BM) and the internal mechanical stress-resilient keratin intermediate filament (IF) network.

Focal adhesions are large, dynamic protein complexes through which the cytoskeleton of a cell connects to the ECM. More than anchoring the cell, they function as signal carriers (sensors), which inform the cell about the condition of the ECM and thus affect their behavior.

Focal contacts are adhesions by which cell attach to the underlying substrate. A large number of specific proteins are known to be concentrated at focal contacts, these are usually structural and cytoskeletal proteins but many are also signalling molecules (Sastry & Burridge, 2000).

Cells adhere to each other and to the extracellular matrix through cell-surface proteins called cell adhesion molecules (CAMs)—a category that includes the transmembrane adhesion proteins we have already discussed. CAMs can be cell-cell adhesion molecules or cell-matrix adhesion molecules.

The cells are attached to each other by cell-cell adhesions, which bear most of the mechanical stresses. For this purpose, strong intracellular protein filaments (components of the cytoskeleton) cross the cytoplasm of each epithelial cell and attach to specialized junctions in the plasma membrane.

Cadherins are transmembrane proteins that mediate cell– cell adhesion in animals. By regulating contact formation and stability, cadherins play a crucial role in tissue morphogenesis and homeostasis.

Generally, proteins that interact to bind cells together are called Intercellular Cell Adhesion Molecules (ICAMs). These include selectins. During blood clotting, selectins on one platelet recognize and bind specific receptors on other platelets, contributing to the clot.

stratified squamous epithelial tissue

Stratified epithelia are more durable and protection is one their major functions. Since stratified epithelium consists of two or more layers, the basal cells divide and push towards the apex, and in the process flatten the apical cells.

Stratified

Collagens Collagens

collagen

dermis

Examples include keratin (hair, nails) and collagen. Proteins that ‘fold’ into glob-like structures are known as globular proteins. Globular proteins are far more common than fibrous proteins. A special and important fibrous protein is collagen, which has three polypeptide chains intertwined in a helical structure.

Vascular and Arthrochalasia Type Collagen I is found in virtually all extracellular matrices, including bone, skin, and tendons while collagen III also is an important component of blood vessels and hollow organs (1). Mutations in collagen type III underlie the vascular type of EDS (EDS type IV).

The secondary structure of insulin is an example of the alpha helix (there are three segments). The intramolecular hydrogen bonding in the alpha-helix is between the amide groups. Insulin also illustrates an important property of many globular proteins.

Collagen is an abundant structural protein in all animals. In humans, collagen comprises one-third of the total protein, accounts for three-quarters of the dry weight of skin, and is the most prevalent component of the extracellular matrix (ECM).

Ways to boost collagen

1. 1) Hyaluronic acid. Hyaluronic acid is an important compound for collagen in the skin.
2. 2) Vitamin C. Vitamin C is one of the best-known vitamins.
3. 3) Aloe vera gel.
4. 4) Ginseng.
5. 5) Antioxidants.
6. 6) Retinol.
7. 7) Red light therapy.
8. 8) Protect the skin from the environment.