Protective protein/cathepsin A rescues N-glycosylation defects in neuraminidase-1.
Protective protein/cathepsin A rescues N-glycosylation defects in neuraminidase-1.
复制标题
保护性蛋白/组织蛋白酶 A 可修复神经氨酸酶 1 中的 N-糖基化缺陷。
DOI：
10.1016/j.bbagen.2009.01.006
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Bonten,Erik
中科院分区：
文献类型：
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作者：
Wang,Dongning;Zaitsev,Slava;Taylor,Garry;d'Azzo,Alessandra;Bonten,Erik
神经氨酸酶-1（NEU 1）分解代谢唾液酸从唾液酸-糖缀合物中水解。NEU 1依赖于其与保护蛋白/组织蛋白酶A（PPCA）的相互作用来进行溶酶体区室化和催化活化。小鼠NEU 1含有4个N-糖基化位点，其中3个在人酶中是保守的。NEU 1的表达产生差异糖基化的蛋白质. METHODS我们在小鼠NEU 1的4个N-糖基化位点中的每一个产生单点突变。在存在和不存在PPCA的情况下，在NEU 1缺陷细胞中表达突变酶。将所有4种N-糖基化变体靶向溶酶体/内体区室。除最C-末端聚糖外，所有N-聚糖对于维持稳定性或催化活性都很重要。通过增加PPCA表达来挽救由第二N-聚糖的缺失引起的催化活性的损失。类似的结果与人类NEU 1的N-糖基化突变体中确定的唾液酸中毒patient. CONCLUSIONSSThe N-末端N-聚糖的NEU 1是必不可少的，其功能，而C-末端N-聚糖似乎是非必需的。省略的第二个N-聚糖可以通过上调PPCA的表达来补偿。一般意义这些发现可能与携带特定NEU 1突变的患者的靶向治疗设计有关。
BACKGROUNDNeuraminidase-1 (NEU1) catabolizes the hydrolysis of sialic acids from sialo-glycoconjugates. NEU1 depends on its interaction with the protective protein/cathepsin A (PPCA) for lysosomal compartmentalization and catalytic activation. Murine NEU1 contains 4 N-glycosylation sites, 3 of which are conserved in the human enzyme. The expression of NEU1 gives rise to differentially glycosylated proteins.METHODSWe generated single-point mutations in mouse NEU1 at each of the 4 N-glycosylation sites. Mutant enzymes were expressed in NEU1-deficient cells in the presence and absence of PPCA.RESULTSAll 4 N-glycosylation variants were targeted to the lysosomal/endosomal compartment. All N-glycans, with the exception of the most C-terminal glycan, were important for maintaining stability or catalytic activity. The loss of catalytic activity caused by the deletion of the second N-glycan was rescued by increasing PPCA expression. Similar results were obtained with a human NEU1 N-glycosylation mutant identified in a sialidosis patient.CONCLUSIONSThe N-terminal N-glycan of NEU1 is indispensable for its function, whereas the C-terminal N-glycan appears to be non-essential. The omission of the second N-glycan can be compensated for by upregulating the expression of PPCA.GENERAL SIGNIFICANCEThese findings could be relevant for the design of target therapies for patients carrying specific NEU1 mutations.