Enhanced stability of microtubules enriched in detyrosinated tubulin is not a direct function of detyrosination level.
Enhanced stability of microtubules enriched in detyrosinated tubulin is not a direct function of detyrosination level.
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DOI：
10.1083/jcb.106.1.141
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发表时间：
1988-01
期刊：
影响因子：
--
通讯作者：
Bulinski JC
中科院分区：
文献类型：
--
作者：
Khawaja S;Gundersen GG;Bulinski JC
间期培养的猴肾 (TC-7) 细胞含有富含翻译后去酪氨酸 (Glu) 或酪氨酸 (Tyr) α 微管蛋白的独特细胞微管 (MT) 子集 (Gundersen, G. G., M. H. Kalnoski 和 J. C. Bulinski. 1984. Cell. 38:779-789)。为了确定这些 MT 子集的相对稳定性，我们对 TC-7 细胞进行了缓慢解聚 MT 的处理。我们发现，在活细胞中，Glu MT 比 Tyr MT 更能抵抗诺考达唑的解聚作用，并且在去污剂透化的细胞模型中，更能抵抗稀释引起的解聚作用。然而，在冷处理的细胞中，Glu 和 Tyr MT 的稳定性没有显着差异。用胰腺羧肽酶 A 消化透化细胞模型，从内源性 Tyr MT 生成 Glu MT，并没有显着改变内源性 Tyr MT 对稀释诱导解聚的抵抗力。此外，在不含有明显 Glu MT 的人成纤维细胞中，我们观察到了诺考达唑耐药 MT 的群体。这些数据表明，Glu MT 对末端介导的解聚具有增强的稳定性，但单独的脱酪氨酸似乎不足以赋予这种增强的稳定性。
Interphase cultured monkey kidney (TC-7) cells contain distinct subsets of cellular microtubules (MTs) enriched in posttranslationally detyrosinated (Glu) or tyrosinated (Tyr) alpha tubulin (Gundersen, G. G., M. H. Kalnoski, and J. C. Bulinski. 1984. Cell. 38:779-789). To determine the relative stability of these subsets of MTs, we subjected TC-7 cells to treatments that slowly depolymerized MTs. We found Glu MTs to be more resistant than Tyr MTs to depolymerization by nocodazole in living cells, and to depolymerization by dilution in detergent- permeabilized cell models. However, in cold-treated cells, Glu and Tyr MTs did not differ significantly in their stability. Digestion of permeabilized cell models with pancreatic carboxypeptidase A, to generate Glu MTs from endogenous Tyr MTs, did not significantly alter the resistance of the endogenous Tyr MTs toward dilution-induced depolymerization. Furthermore, in human fibroblasts that contained no distinct Glu MTs, we observed a population of nocodazole-resistant MTs. These data suggest that Glu MTs possess enhanced stability against end- mediated depolymerization, yet detyrosination alone appears to be insufficient to confer this enhanced stability.