Elastic fiber

Elastic fiber
Subcutaneous tissue from a young rabbit. Highly magnified. (Elastic fibers labeled at right. )
Dorlands /Elsevier	f_05/12360925
Anatomical terminology []

Elastic fibers (or yellow fibers) are bundles of proteins (elastin) found in extracellular matrix of connective tissue and produced by fibroblasts and smooth muscle cells in arteries. These fibers can stretch up to 1.5 times their length, and snap back to their original length when relaxed. Elastic fibers include elastin, elaunin and oxytalan.

Elastic tissue is classified as "connective tissue proper".

The elastic fiber is formed from the elastic microfibril (consisting of numerous proteins such as microfibrillar-associated glycoproteins, fibrillin, fibullin, and the elastin receptor) and amorphous elastin.

The microfibril scaffolds and organizes the deposition of amorphous elastin. Amorphous elastin forms from monomers of soluble tropoelastin which is insolubilized and crosslinked into amorphous elastin by lysyl oxidase. Lysyl oxidase reacts with specific lysine residues and by oxidative deamination generates reactive aldehydes and allysine.

These reactive aldehydes and allysines can react with lysine and other allysine residues to crosslink and form desmosine, isodesmosine, and a number of other polyfunctional crosslinks that join surrounding elastin molecules to build an elastin matrix and elastic fiber. These unique crosslinks are responsible for elastin's elasticity.