Major structural protein of tissues such as aorta and nuchal ligament, which must expand rapidly and recover completely. Molecular determinant of the late arterial morphogenesis, stabilizing arterial structure by regulating proliferation and organization of vascular smooth muscle (By similarity). The polymeric elastin chains are cross-linked together into an extensible 3D network. Forms a ternary complex with BGN and MFAP2. Interacts with MFAP2 via divalent cations (calcium > magnesium > manganese) in a dose-dependent and saturating manner. Interacts with FBLN5 and FBN1. Forms a ternary complex with FBN1 and FBLN2 or FBLN5. Interacts with MFAP4 in a Ca (2+)-dependent manner; this interaction promotes ELN self-assembly (By similarity). Interacts with EFEMP2 with moderate affinity (By similarity). Extracellular matrix of elastic fibers. Experimental confirmation may be lacking for some isoforms. Down-regulated by DTR via activation of EGFR. Elastin is formed through the cross-linking of its soluble precursor tropoelastin. Cross-linking is initiated through the action of lysyl oxidase on exposed lysines to form allysine. Subsequent spontaneous condensation reactions with other allysine or unmodified lysine residues result in various bi-, tri-, and tetrafunctional cross-links. The most abundant cross-links in mature elastin fibers are lysinonorleucine, allysine aldol, desmosine, and isodesmosine. Hydroxylation on proline residues within the sequence motif, GXPG, is most likely to be 4-hydroxy as this fits the requirement for 4-hydroxylation in vertebrates. Belongs to the elastin family.