Endoglin is a type I membrane glycoprotein located on cell surfaces and is part of the TGF beta receptor complex. The protein consists of a homodimer of 180 kDA with disulfide links. It has been found on endothelial cells, activated macrophages, fibroblasts, and smooth muscle cells. Endoglin has been found to be part of the TGF-beta1 receptor complex. It thus may be involved in the binding of TGF-beta1, TGF-beta3, activin-A, BMP-2, and BMP-7. In humans endoglin may be involved in the autosomal dominant disorder known as hereditary hemorrhagic telangiectasia type 1. This condition leads to frequent nose bleeds, telangiectases on skin and mucosa and may cause arteriovenous malformations in different organs including brain, lung, and liver.
