Shaw Gerry, Yang Cui, Zhang Lu, Cook Petra, Pike Brian, Hill William D
Department of Neuroscience, University of Florida College of Medicine, McKnight Brain Institute, Gainesville, FL 32610, USA.
Biochem Biophys Res Commun. 2004 Dec 10;325(2):619-25. doi: 10.1016/j.bbrc.2004.09.223.
Neurofilaments are the major components of the neuronal cytoskeleton, and accumulations of these proteins are associated with several important human diseases. Here we report the cloning and sequencing of bovine NF-M, the first NF-M cloned from a large domestic mammal. The bovine sequence proves to be generally more similar to that of human NF-M than the previously described mammalian sequences, suggesting that bovine neurofilaments are a useful model for biochemical studies of application to humans. However, we noted some unusual features within the 16 lys-ser-pro (KSP2) type phosphopeptide repeats and also note that the number of these repeats correlates well with the size of animal. We also characterized two in vitro calpain cleavage sites by direct peptide sequencing, finding that both are located in the glutamic acid rich E segment. Finally, we show biochemically that the more abundant and stable of these calpain fragments can also be detected in vivo.
神经丝是神经元细胞骨架的主要成分，这些蛋白质的积累与几种重要的人类疾病相关。在此，我们报告牛源NF-M的克隆与测序，这是首个从大型家养哺乳动物中克隆出的NF-M。结果表明，牛源序列总体上比先前描述的哺乳动物序列与人类NF-M的序列更为相似，这表明牛神经丝是用于人类生化研究的有用模型。然而，我们注意到16个赖氨酸-丝氨酸-脯氨酸（KSP2）型磷酸肽重复序列中有一些不寻常的特征，并且还注意到这些重复序列的数量与动物的大小密切相关。我们还通过直接肽测序对两个体外钙蛋白酶切割位点进行了表征，发现这两个位点均位于富含谷氨酸的E段。最后，我们通过生化方法表明，这些钙蛋白酶片段中更丰富、更稳定的片段在体内也能被检测到。
