THE E-SELECTIN-LIGAND ESL-1 IS A VARIANT OF A RECEPTOR FOR FIBROBLASTGROWTH-FACTOR

E-SELECTIN is an inducible cell-adhesion molecule on endothelial cells , which mediates the binding of neutrophils and functions as a Ca2+-de pendent lectin(1-3). We have recently identified a 150K glycoprotein a s the major ligand for E-selectin on myeloid cells, using a recombinan t antibody-like form of mouse E-selectin as an affinity probe(4,5). He re we report the isolation of a mouse complementary DNA for this E-sel ectin ligand (ESL-1). The predicted amino-acid sequence of ESL-1 is 94 % identical (over 1,078 amino acids) to the recently identified chicke n cysteine-rich fibroblast growth-factor receptor(6), except for a uni que 70-amino-acid amino-terminal domain of mature ESL-1. Fucosylation of ESL-1 is imperative for affinity isolation with E-selectin-IgG. A f ucosylated, recombinant antibody-like form of ESL-1, but not for L-sel ectin, supports adhesion of E-selectin-transfected Chinese hamster ova ry cells. Antibodies against ESL-1 block the binding of mouse myeloid cells to E-selectin. ESL-1, with a structure essentially identical to that of a receptor, thus functions as a cell adhesion ligand of E-sele ctin.