Endomucin (endothelial sialomucin; also Endomucin-1/2 and Mucin-14) is an 80 - 120 kDa glycoprotein member of the Endomucin family of proteins. It is expressed on endothelial cells and depending upon its glycosylation pattern, can serve as either a pro- or anti-adhesive molecule.
Mouse Endomucin precursor is 261 amino acids in length. It is type I transmembrane protein that contains a 170 aa extracellular domain (ECD) (aa 21 - 190) and a 50 aa cytoplasmic region. Three splice variants exist in the ECD of Endomucin. One shows a deletion of aa 91 - 141, a second shows a one aa substitution for aa 91 - 129, and a third shows a one aa substitution for aa 129 - 142. Over aa 21 - 90, mouse Endomucin shares 60% and 30% aa identity with rat and human Endomucin, respectively.