ESL-1

E-Selectin ligand-1/ESL-1 (GLG1, Golgi complex-Localized Glycoprotein 1; CFR1, MG160 and Cysteine-rich FGF receptor) is a 150-160 kDa glycoprotein. The amino acid sequence of MG160, a membrane sialoglycoprotein of the medial cisternae of the rat Golgi apparatus, is more than 90% identical with CFR, a fibroblast growth factor (FGF) binding protein of chicken membranes, and with ESL-1, a ligand for E-selectin of plasma membranes of myeloid cells; furthermore, MG160, isolated by immunoaffinity chromatography from rat brain membranes, binds to basic FGF. The protein has a large luminal domain composed of an initial Proline-Glutamine-rich segment, encoded by an uninterrupted exonic sequence of several CAG-CAA repeats. Expansion of CAG repeats has been implicated in the etiology of several neurodegenerative diseases. The Proline-Glutamine-rich segment is followed by 16 cysteine-rich repeats that contain five potential Asparagine-linked glycosylation sites, which are conserved in the human, rat, mouse, and chicken. The large extracellular domain of the protein is followed by a single transmembrane domain and a 13-amino-acid cytoplasmic carboxy-terminal tail, which is identical to that in the chicken, rat, and mouse. It is expressed in both Golgi and/or the cell membrane of multiple cell typs, including liver stellate cells, neurons, cardiac myocytes, monocytes and bronchial epithelial cells. In the blood, GLG1/ESL-1 collaborates with PSGL-1 to mediate leukocyte binding to endothelial cell surfaces