Connective tissue must be able to withstand the repeated stretching of dynamic structures such as arterial walls, lung and skin. Elastic fibres in the extracellular matrix endow connective tissue with the necessary resilience and elasticity, complementing collagen fibrils, which provide tensile strength. These fibres are extremely complex, and only recently has an understanding of their many components and multistep assembly process begun to emerge. In a Commentary on , Cay Kielty and co-workers review recent work that has shed light on elastic fibre biology. Ultrastructural approaches, for example,suggest that intramolecular folding of fibrillin, which forms head-to-tail arrays in elastic fibre microfibrils, drives their extension and recoil, which contributes to the elastic properties of the fibres. Moreover, in vitro binding studies have revealed how fibrillins interact with other elastic fibre molecules, such as matrix-associated glycoprotein 1 (MAGP-1) and the elastin precursor tropoelastin. The importance of these molecules is evident from analyses of knockout mice lacking elastin or fibrillin 1, which exhibit vascular defects owing to defective formation of elastic fibres in arterial walls.
