Emilin-1

Emilins (elastin microfibril interface located proteins) are extracellular matrix glycoproteins that localize to sites with proximity to elastin and microfibrils. They consist of an N-terminal cysteine-rich EMI domain and a conserved C-terminal gC1q-like domain. Emilin-1 is abundant in elastin-rich tissues such as blood vessels, skin, heart and lung. It influences placenta formation and initial organogenesis with a later role in interstitial connective tissue. Emilin-2 is larger than Emilin-1 and contains a unique proline-rich domain. It is likely involved in the process of elastogenesis. Multimerin-2 (also known as Emilin-3 or EndoGlyx-1) is expressed during embryonic development. Multimerin-1 (also known as Emilin-4) is expressed in platelets and the endothelium of blood vessels and may act as a carrier protein for platelet factor V. Emilin-5 is encoded by the Emilin-3 gene and is sometimes referred to as Emilin-3. It contains the N-terminal cysteine-rich EMI domain but lacks the C-terminal gC1q-like domain. Emilin-1 have been shown to be expressed in smooth muscle and other mesenchymal tissues and is localized at the proximity of elastin and microfibrils. Emilin-1 exerts an important role in lymphatic system, being a crucial structural molecule that regulates the formation of lymphatic capillaries and collectors. Emilin-1 through the interaction with the α4β1 integrin via the C-terminal gC1q domain exerts a negative effect on proliferation. It binds pro-TGFβ preventing its maturation to mature TGFβ in the extracellular space, therefore influencing the regulation of blood and lymph vessels formation and maintenance.