Identification of human endomucin-1 and -2 as membrane-bound O-sialoglycoproteins with anti-adhesive activity11The nucleotide sequences reported in this paper are available via GenBank accession numbers AB034694 (mouse endomucin-1), AB034695 (human endomucin-1), and AB034696 (human endomucin-2).

AbstractUsing a signal sequence trap method and database search, we identified a series of human cDNAs encoding two structurally related type I membrane proteins of ∼25 kDa with multiple glycosylation motifs. These genes, termed endomucin-1/-2, are expressed in several human tissues including heart, kidney, and lung. Exogenously expressed human endomucin-1/-2 proteins were modified into 80–120 kDa glycoproteins, which were susceptible to O-sialoglycoprotein endopeptidase digestion. Transient overexpression of endomucin-1/-2 reduced the number of adhesion plaques and reduced cell attachment to the substrate. This phenotype was suppressed by laminin or the protein kinase inhibitor staurosporine. Our findings suggest that human endomucin-1/-2 negatively regulate cell adhesion to the extracellular matrix