Nakada H, Inoue M, Yamashina I
Department of Biotechnology, Faculty of Engineering, Kyoto Sangyo University, Kita-ku, Japan.
Biochem Biophys Res Commun. 1997 May 29;234(3):559-63. doi: 10.1006/bbrc.1997.6683.
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.
从一名结直肠癌患者的腹水中分离出携带唾液酸化LeA抗原的粘蛋白型糖蛋白（SL-GP）。SL-GP以依赖钙离子和唾液酸化LeA抗原的方式与内皮细胞上的E-选择素结合。为了研究由结合导致的E-选择素的代谢变化，用32P-磷酸盐或35S-甲硫氨酸和35S-半胱氨酸标记内皮细胞。与SL-GP结合而非与唾液酸化LeA六糖结合可使E-选择素一个或多个丝氨酸残基的磷酸化增加。在SL-GP存在的情况下用35S-甲硫氨酸和35S-半胱氨酸对E-选择素进行脉冲标记表明，SL-GP结合可加速E-选择素的降解，但在与SL-GP预结合后进行标记显示E-选择素的合成增加。这种合成可能反映了对预结合时降解的E-选择素的补偿。这些结果表明，SL-GP的结合增强了E-选择素的整体代谢，降解和合成明显平衡。
