Metabolic changes of E-selectin caused by the binding of a mucin carrying sialylLewis A antigens.
Mucin-type glycoproteins carrying sialylLeA antigens (SL-GP) were isolated from the ascites fluid of a patient with colorectal cancer. SL-GP bound to E-selectin on endothelial cells in Ca2+- and sialylLeA antigen-dependent manners. To examine the metabolic change in E-selectin caused by ligation, endothelial cells were labeled with 32P-phosphate or 35S-Met and 35S-Cys. Phosphorylation at one or more serine residues of E-selectin was elevated by ligation with SL-GP but not with sialylLeA hexasaccharide. Pulse-labeling of E-selectin with 35S-Met and 35S-Cys in the presence of SL-GP indicated that the degradation of E-selectin was accelerated by SL-GP ligation, but labeling after pre-ligation with SL-GP revealed an increase in the synthesis of E-selectin. The synthesis may reflect compensation for the E-selectin degraded on pre-ligation. These results indicate that the overall metabolism of E-selectin was enhanced by the ligation of SL-GP, with degradation and synthesis being apparently balanced.
Nakada
H
H
Department of Biotechnology, Faculty of Engineering, Kyoto Sangyo University, Kita-ku, Japan.
Inoue
M
M
Yamashina
I
I
D018395:CA-19-9 Antigen; D002478:Cells, Cultured; D019040:E-Selectin / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism; D005732:Gangliosides / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D009077:Mucins / Q000276:immunology / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D013462:Sulfur Radioisotopes
D018395:CA-19-9 Antigen; D019040:E-Selectin; D005732:Gangliosides; D009077:Mucins; D013462:Sulfur Radioisotopes; C064564:sialyl Le(a) ganglioside