Fibrillins are the primary constituents of the microfibrills in the extracellular matrix of many elastic and non-elastic connective tissues. They consists of an N-terminal fibrillin unique domain (FUN) (Pfam:PF18193) and several calcium-binding epidermal growth factor-like (cbEGF-like) domains [1]. This entry represents the first EGF-like domain which together with FUN, contributes to the binding to cbEGFs [1].

1: Structure of the fibrillin-1 N-terminal domains suggests that heparan sulfate regulates the early stages of microfibril assembly. Yadin DA, Robertson IB, McNaught-Davis J, Evans P, Stoddart D, Handford PA, Jensen SA, Redfield C; Structure. 2013;21:1743-1756. PMID:24035709