élastine

Elastin is a crucial protein in the extracellular matrix that provides elasticity and resilience to vertebrate tissues. It is a key component of connective tissues such as skin, lungs, blood vessels, and ligaments. Elastin is synthesized as a soluble precursor called tropoelastin, which is secreted by cells and then cross-linked extracellularly to form mature, insoluble elastin fibers. This cross-linking process involves enzymes like lysyl oxidase and results in a complex network of elastic fibers that can stretch and recoil.

The unique properties of elastin are attributed to its amino acid composition, which is rich in glycine, alanine, and valine, with a significant proportion of proline and lysine residues. These amino acids contribute to the protein's disordered, random coil structure, which allows it to stretch and absorb energy. When the stretching force is removed, the hydrophobic interactions within the elastin molecule drive it to recoil to its original state. This elasticity is vital for the function of many organs; for example, it allows arteries to expand and contract with each heartbeat and skin to return to its shape after being pulled.

The production of elastin is highest during development and decreases significantly with age. This decline in elastin content and function contributes to the aging process, leading to wrinkles, loss of skin firmness, and reduced cardiovascular elasticity. Diseases affecting elastin, such as Marfan syndrome and cutis laxa, highlight the critical role of this protein in maintaining tissue integrity and function. Research into elastin is ongoing, seeking to understand its assembly, degradation, and potential therapeutic applications for age-related conditions and connective tissue disorders.