The significance of phosphorylation of neurofilament protein

在神经元中，神经丝（NF）在体细胞和树突中相对较少，但在轴突中丰富。除了这种非极性外，NF亚基蛋白，特别是NF- h，在轴突中被极度磷酸化，而在体细胞和树突中磷酸化的程度要小得多。NF-H对于在核心细丝之间形成交叉桥至关重要，我们认为它的磷酸化似乎是形成良好的交叉桥所必需的。为了证实我们的想法，我们在这三年中获得了NF- h磷酸化与NF组织之间关系的五个主要结果。1）.核丝和交叉桥排列规则，NF-H在较厚的有髓轴突中磷酸化良好，而在微管明显的较薄轴突中则不那么规则，磷酸化较少。2）.在Ranvier节点，轴突直径变小，核心丝相互靠近，交叉桥不那么规则，NF-H的磷酸化程度低于t。3）.将NF-H蛋白微注射到培养的非神经元细胞或神经元样细胞中，NF-H被纳入中间丝中，磷酸化后在交叉桥中形成纤维束的频率较高。4)。体外实验表明，NF可以通过NF- h形成的交叉桥与微管或线粒体相互作用，尽管我们现在正在研究NF- h磷酸化的哪种条件对这种相互作用更有效。5)。目前，我们正在阐明髓鞘形成与NF组织或NF- h磷酸化之间的关系，在中枢神经系统中，髓鞘形成被破坏。刚刚发现，非磷酸化形式的NF-H急剧增加，髓磷脂缺乏轴突的核心细丝比对照组紧密得多。综上所述，我们的数据表明NF- h磷酸化与NF组织之间存在密切的关系，并且NF- h磷酸化是轴突在交叉桥和最终在核心细丝中有规则排列的必要条件。此外，我们认为髓鞘形成增加了NF- h磷酸化水平，导致轴突中正常的NF组织。少

In neurons, neurofilaments (NF) are relatively fewer in somata and dendrites but abundant in axons. In addition to this NFpolarity, the NF subunit protein, especially NF-H,is extremely phosphorylated in axons, and much less phosphorylated in somata and dendrites. NF-H is essential for forming crossbridges between core filaments, and we are thinking that its phosphorylation seems necessary to form well-developed crossbridges. To confirm our idea, we have obtained five main results on the relationship between NF-H phosphorylation and NF organization during these three years. 1).Both core filaments and crossbridges were regular in arrangement and NF-H was well phosphorylated in thicker myelinated axons, whereas they were less regular and less phosphorylated in thinner axons where microtubules were conspicuous. 2).In the node of Ranvier, where axon becomes smaller in diameter, core filametns were closer to each other and crossbridges were less regular and NF-H wa less phosphorylated than t … More he remainder of the same axon. 3).After microinjection of NF-H protein into cultured nonneuronal or neuron-like cells, NF-H was incorported into intermediate filaments and tended to make bundles of the filaments with rather higher frequency in crossbridges when it was phosphorylated. 4).In vitro experiments showed that NF could interact with microtubules or mitochondria through the crossbridges formed by NF-H,although we are now examining which condition in phosphorylation of NF-H is more efficient for such interactions. 5).At present, we are clarifying the relationship between the myelination and NF organization or NF-H phosphorylation with jimpy mutanat mice, where the myelinogenesis is distrupted in the central nervous system. It has just been found that nonphosphorylated form of NF-H increases drastically and core filaments are much more compact in the myelin-deficient axons than in controls. In conclusion, our data indicate that there is an intimate relationship between NF-H phosphorylation and NF organization, and also that it is necessary for the axon to have regular arrangements in crossbridges and finally in core filaments by NF-H phosphorylation. Furthermore, it is considered that the myelination increases in NF-H phosphorylation level resulting in normal NF oganization in axons. Less