Loss of Core Fucosylation of Low-Density Lipoprotein Receptor–Related Protein-1 Impairs Its Function, Leading to the Upregulation of Serum Levels of Insulin-Like Growth Factor–Binding Protein 3 in Fut8?/? Mice

摘要

α1,6-Fucosyltransferase (Fut8) catalyzes the transfer of a fucose residue from GDP-fucose to the innermost N-acetylglucosamine residue of N-glycans. Here we report that the loss of core fucosylation impairs the function of low-density lipoprotein (LDL) receptor–related protein-1 (LRP-1), a multifunctional scavenger and signaling receptor, resulting in a reduction in the endocytosis of insulin like growth factor (IGF)–binding protein-3 (IGFBP-3) in the cells derived from Fut8-null (Fut8−/−) mice. The reduced endocytosis was restored by the re-introduction of Fut8. Serum levels of IGFBP-3 were markedly upregulated in Fut8−/− mice. These data clearly indicate that core fucosylation is crucial for the scavenging activity of LRP-1 in vivo.