THE SEA MODULE - A NEW EXTRACELLULAR DOMAIN ASSOCIATED WITH O-GLYCOSYLATION

Using a variety of homology search methods and multiple alignments, a new extracellular module was identified in (1) agrin, (2) enterokinase , (3) a 63-kDa sea urchin sperm protein, (4) perlecan, (5) the breast cancer marker MUC1 (episialin), (6) the cell surface antigen 114/A10, and (7/8) two functionally uncharacterized, probably extracellular, Ca enorhabditis elegans proteins. Despite the functional diversity of the se adhesive proteins, a common denominator seems to be their existence in heavily glycosylated environments. In addition, the better charact erized proteins mentioned above contain all O-glycosidic-linked carboh ydrates such as heparan sulfate that contribute considerably to their molecular masses. The common module might regulate or assist binding t o neighboring carbohydrate moieties.