Figure 1

Schematic structure of ICAM-2 and ICAM-2 variants. Schematic representation of the structures of ICAM-2 and hypo-glycosylated ICAM-2 glycosylation site variants (gsv). ICAM-2 wild type (WT) contains six glycosylated amino acids in its extracellular domain (ED), at residues 47, 82, 105, 153, 176 and 187. The ED also contains two immunoglobulin-like domains (designated IgLD-1 and -2). Short transmembrane (TD) and cytoplasmic (CD) domains are also present. The N-terminus of the nascent protein contains a 21-amino acid signal peptide (sp) that is not present in the 254 amino acid mature protein. Variants were constructed by substituting alanines (A) for asparagines (N) at the indicated amino acid residues. For example, gsv1,4,5 contains alanines at mutation sites 1, 4, and 5 (amino acids 47, 153, and 176); therefore, gsv1,4,5 is not able to be glycosylated at these three sites. Variant gsv1-6 has alanines at all six glycosylation sites, and is non-glycosylated when expressed in SK-N-AS cell transfectants.