Studies on a role of autophagy on the catabolism of sialylated oligosaccharides

先前，我们发现在Atg5^<-/->细胞中，唾液寡糖特异性地积聚在细胞质中。在非饥饿条件下观察到这些聚糖的积累，表明非诱导的基础自噬对它们的分解代谢是必不可少的。有趣的是，一旦在细胞质中积累，唾液醛聚糖就不能通过自噬过程的恢复而有效地分解代谢，这表明功能性自噬对于防止唾液醛低聚糖在细胞质中积累很重要。此外，唾液酸的溶酶体转运体sialin的敲低导致唾液寡糖的显著减少，这表明自噬影响了这种转运体的底物特异性。因此，这项研究提供了基础自噬和n链聚糖分解代谢之间令人惊讶的联系。

Previously, we showed that in Atg5^<-/-> cells, sialyl oligosaccharides specifically accumulated in the cytosol. Accumulation of these glycans was observed under non-starved conditions, suggesting that non-induced, basal autophagy is essential for their catabolism. Interestingly, once accumulated in the cytosol, sialyl glycans cannot be efficiently catabolized by resumption of the autophagic process, suggesting that functional autophagy is important for preventing sialyl oligosaccharides from accumulating in the cytosol. Moreover, knockdown of sialin, a lysosomal transporter of sialic acids, resulted in a significant reduction of sialyl oligosaccharides, implying that autophagy affects the substrate specificity of this transporter. This study thus provides a surprising link between basal autophagy and catabolism of N-linked glycans.