Respective roles of neurofilaments, microtubules, MAP1B, and tau in neurite outgrowth and stabilization.
Respective roles of neurofilaments, microtubules, MAP1B, and tau in neurite outgrowth and stabilization.
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DOI：
10.1091/mbc.5.8.863
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发表时间：
1994-08
影响因子：
3.3
通讯作者：
Thomas B. Shea;M. Beermann
中科院分区：
文献类型：
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作者：
Thomas B. Shea;M. Beermann
在DBcAMP处理过程中，通过向瞬时通透性的NB2a/D1细胞内递送特定的抗血清，探讨了神经丝(NFS)、微管(MTS)和微管相关蛋白(MAP1B)和tau在轴突生长和稳定中的各自作用。细胞内递送针对低(NF-L)、中(NF-M)或广泛磷酸化的高分子(NF-H)亚基的抗血清并不能阻止最初的突起形成，也不能诱导先前用DBcAMP处理1d的细胞所形成的现有突起的回缩。相反，在这两个时间点，细胞内注射针对微管蛋白的抗血清降低了有神经突起的细胞的百分比。细胞内注射抗核因子-L和抗核因子-M抗血清3d后，细胞内注射针对广泛磷酸化的核因子-H、MAP1B、tau或微管蛋白的抗血清均未引起细胞的轴突收缩，但此时可引起相似水平的轴突收缩。针对磷酸化的NF-H诱导的轴突收缩的单抗(RT97或SMI-31)在用DBcAMP处理3d后的细胞内传递，而针对非磷酸化的NF-H的单抗(SMI-32)此时不能诱导轴突的收缩。与之相反，上述抗血清均不能诱导DBcAMP处理7d的神经突起回缩。突起对秋水仙碱的回缩产生抵抗，部分突起在3d后出现，多数突起在7d后出现。因此，我们研究了上述抗血清的细胞内递送是否降低了秋水仙碱的耐药性。秋水仙碱处理后，细胞内注射针对广泛磷酸化的NF-H、MAP1B或tau的抗血清后，细胞内出现迅速的突起回缩。相反，秋水仙碱的耐药性不会因针对NF-L、NF-M或微管蛋白的抗血清而受到影响。这些发现支持先前的研究，即MT聚合调节轴突生长的某些方面，并提示神经纤维不直接参与这些事件。这些发现进一步表明，在轴突细胞骨架的稳定方面，明显是通过由核因子-H和MAP介导的神经纤维和MTS之间的相互作用来实现的。
The respective roles of neurofilaments (NFs), microtubules (MTs), and the microtubule-associated proteins (MAPs) MAP 1B and tau on neurite outgrowth and stabilization were probed by the intracellular delivery of specific antisera into transiently permeabilized NB2a/d1 cells during treatment with dbcAMP. Intracellular delivery of antisera specific for the low (NF-L), middle (NF-M), or extensively phosphorylated high (NF-H) molecular weight subunits did not prevent initial neurite elaboration, nor did it induce retraction of existing neurites elaborated by cells that had been previously treated for 1 d with dbcAMP. By contrast, intracellular delivery of antisera directed against tubulin reduced the percentage of cells with neurites at both these time points. Intracellular delivery of anti-NF-L and anti-NF-M antisera did not induce retraction in cells treated with dbcAMP for 3 d. However, intracellular delivery of antisera directed against extensively phosphorylated NF-H, MAP1B, tau, or tubulin induced similar levels of neurite retraction at this time. Intracellular delivery of monoclonal antibodies (RT97 or SMI-31) directed against phosphorylated NF-H induced neurite retraction in cell treated with dbcAMP for 3 d; a monoclonal antibody (SMI-32) directed against nonphosphorylated NF-H did not induce neurite retraction at this time. By contrast, none of the above antisera induced retraction of neurites in cells treated with dbcAMP for 7 d. Neurites develop resistance to retraction by colchicine, first detectable in some neurites after 3 d and in the majority of neurites after 7 d of dbcAMP treatment. We therefore examined whether or not colchicine resistance was compromised by intracellular delivery of the above antisera. Colchicine treatment resulted in rapid neurite retraction after intracellular delivery of antisera directed against extensively phosphorylated NF-H, MAP1B, or tau into cells that had previously been treated with dbcAMP for 7 d. By contrast, colchicine resistance was not compromised by the intracellular delivery of antisera directed against NF-L, NF-M, or tubulin. These findings support previous studies indicating that MT polymerization mediates certain aspects of axonal neurite outgrowth and suggest that NFs do not directly participate in these events. These findings further suggest that NFs function in stabilization of the axonal cytoskeleton, apparently by interactions among NFs and MTs that are mediated by NF-H and MAPs.