Cytoplasmic O-GlcNAc modification of the head domain and the KSP repeat motif of the neurofilament protein neurofilament-H
Cytoplasmic O-GlcNAc modification of the head domain and the KSP repeat motif of the neurofilament protein neurofilament-H
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DOI：
10.1074/jbc.271.34.20845
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发表时间：
1996-08-23
影响因子：
4.8
通讯作者：
Cleveland, DW
中科院分区：
文献类型：
--
作者：
Dong, DLY;Xu, ZS;Cleveland, DW
神经丝是大型有髓神经元中的主要中间纤维，对于确定适当的轴突口径至关重要。哺乳动物神经丝是由神经丝（NF）-H、NF-M和NF-L三种多肽组装而成的专性杂聚物，每种多肽在多个位点处经历磷酸化。已知NF-M和NF-L被O-连接的N-乙酰葡糖胺（O-GlcNAc）修饰（Dong，D. L-是的，徐志-美国，Chevrier，M. R.，科特河J.，克利夫兰，D。W.，和哈特，G. W.（1993）J.Biol.Chem.268，16679-16687），在此我们进一步报道了NF-H在头部结构域中的Thr（53）、Ser（54）和Ser（56）处被O-GlcNAc广泛修饰，并且有些令人惊讶地，在尾部结构域中的Lys-Ser-Pro重复基序内的多个位点处被O-GlcNAc广泛修饰，已知在组装的神经丝中的一个区域在每个类似于50个KSP重复上几乎化学计量地磷酸化。除了先前鉴定的NF-M和NF-L上的位点之外，这里还确定了NF-M的Thr（19）和Ser（34）以及MF-L的Ser（34）和Ser（48）上的O-GlcNAc位点，所有这些位点都位于对细丝组装至关重要的头部结构域序列中，O的接近度-每个亚基头部和尾部结构域中的GlcNAc和磷酸化位点表明这些修饰可能相互影响并在纤维中发挥作用组装和网络形成。
Neurofilaments, the major intermediate filaments in large myelinated neurons, are essential for specifying proper axonal caliber. Mammalian neurofilaments are obligate heteropolymers assembled from three polypeptides, neurofilament (NF)-H, NF-M, and NF-L, each of which undergoes phosphorylation at multiple sites. NF-M and NF-L are known to be modified by O-linked N-acetylglucosamine (O-GlcNAc) (Dong, D. L.-Y., Xu, Z.-S., Chevrier, M. R., Cotter, R. J., Cleveland, D. W., and Hart, G. W. (1993) J. Biol. Chem. 268, 16679-16687), Here we further report that NF-H is extensively modified by O-GlcNAc at Thr(53), Ser(54), and Ser(56) in the head domain and, somewhat surprisingly, at multiple sites within the Lys-Ser-Pro repeat motif in the tail domain, a region in assembled neurofilaments known to be nearly stoichiometrically phosphorylated on each of the similar to 50 KSP repeats. Beyond the earlier identified sites on NF-M and NF-L, O-GlcNAc sites on Thr(19) and Ser(34) of NF-M and Ser(34) and Ser(48) of MF-L are also determined here, all of which are localized in head domain sequences critical for filament assembly, The proximity of O-GlcNAc and phosphorylation sites in both head and tail domains of each subunit indicates that these modifications may influence one another and play a role in filament assembly and network formation.