The WSAWS motif is C-hexosylated in a soluble form of the erythropoietin receptor
The WSAWS motif is C-hexosylated in a soluble form of the erythropoietin receptor
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DOI：
10.1021/bi034112p
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发表时间：
2003-07-22
期刊：
影响因子：
2.9
通讯作者：
Hofsteenge, J
中科院分区：
文献类型：
--
作者：
Furmanek, A;Hess, D;Hofsteenge, J
WSXWS基序是I型细胞因子受体家族的高度保守的结构特征。先前已经证明，由于细胞内转运缺陷，促红细胞生成素受体（EPOR）中（232）WSAWS（236）基序的突变可导致强烈抑制的表面表达[希尔顿，D. J.，等人（1996）J.Biol.Chem.271，4699-4708]。在这里，我们报告，在HEK-EBNA细胞中表达的重组EPOR胞外结构域（sEPOR）的基序中的第一个色氨酸携带C-连接的己糖残基。S233 A突变完全消除了sEPOR的分泌，而A234 E突变导致分泌增强。野生型蛋白质和从条件培养基和/或细胞分离的突变蛋白质中的C-己糖基化水平的比较表明，基序的C-己糖基化在sEPOR的正确细胞内转运中不起作用。
The WSXWS motif is a highly conserved structural feature of the type I cytokine receptor family. It has previously been demonstrated that mutations in the (232)WSAWS(236) motif in the erythropoietin receptor (EPOR) can result in strongly inhibited surface expression, due to defective intracellular transport [Hilton, D. J., et al. (1996) J. Biol. Chem. 271, 4699-4708]. Here we report that the first tryptophan in the motif of the recombinant extracellular domain of EPOR (sEPOR) expressed in HEK-EBNA cells carries a C-linked hexosyl residue. The S233A mutation completely abolished secretion of sEPOR, whereas the A234E mutation resulted in enhanced secretion. Comparison of the level of C-hexosylation in the wild-type protein and in the mutant proteins isolated from the conditioned medium and/or the cells suggested that C-hexosylation of the motif did not play a role in the correct intracellular transport of sEPOR.