Endothelial sialomucin, also called endomucin or mucin-like sialoglycoprotein, which interferes with the assembly of focal adhesion complexes and inhibits interaction between cells and the extracellular matrix. Consistently localized to the plasma membrane and less abundantly to Golgi-like perinuclear stacks. Expressed in heart, kidney and lung. Highly O-glycosylated. Sialic acid-rich glycoprotein.