Abstract：
Altered glycosylation is a common feature of cancer cells. Some subsets of glycans are found to be frequently enriched on the tumor cell surface and implicated in different tumor phenotypes. Among these, changes in sialylation have long been associated with metastatic cell behaviors such as invasion and enhanced cell survival. Sialylation typically exists in three prominent linkages: α2,3, α2,6, and α2,8, catalyzed by a group of sialyltransferases. The aberrant expression of all three linkages has been related to cancer progression. The increased α2,6 sialylation on N-glycans catalyzed by β-galactoside α2,6 sialyltransferase 1 (ST6Gal1) is frequently observed in many cancers. In contrast, functions of α2,3 sialylation on N-glycans catalyzed by at least three β-galactoside α2,3-sialyltransferases, ST3Gal3, ST3Gal4, and ST3Gal6 remain elusive due to a possibility of compensating for one another. In this minireview, we briefly describe functions of sialylation and recent findings that different α2,3 sialyltransferases specifically modify target proteins, as well as sialylation regulatory mechanisms vis a complex formation among integrin α3β1, Golgi phosphoprotein 3 (GOLPH3), phosphatidylinositol 4-kinase IIα (PI4KIIα), focal adhesion kinase (FAK) and sialyltransferase, which suggests a new concept for the regulation of glycosylation in cell biology.
摘要：
糖基化改变是癌细胞的共同特征。发现聚糖的一些子集经常在肿瘤细胞表面上富集并且涉及不同的肿瘤表型。其中,唾液酸化的变化长期以来与转移性细胞行为有关，例如侵袭和增强细胞存活。唾液酸化通常存在于三个显著的连接中:α2,3、α2,6和α2,8,由一组唾液酸转移酶催化。所有三个连接的异常表达与癌症进展有关。在许多癌症中经常观察到由β-半乳糖苷α2,6唾液酸转移酶1（ST6Gal1）催化的N-聚糖上的α2,6唾液酸化增加。相比之下,α2,3唾液酸化对至少三种β-半乳糖苷α2,3-唾液酸转移酶催化的N-聚糖的功能，ST3Gal3、ST3Gal4和ST3Gal6由于相互补偿的可能性而仍然难以捉摸。在这篇小型评论中，我们简要描述唾液酸化的功能和最近的发现，不同的α2,3唾液酸转移酶特异性修饰靶蛋白，以及唾液酸化调节机制与整合素α3β1，高尔基磷蛋白3（GOLPH3）之间的复合物形成，磷脂酰肌醇4-激酶IIα(PI4KIIα),粘着斑激酶（FAK）和唾液酸转移酶，这提出了细胞生物学中糖基化调控的新概念。
