Distribution of tyrosinated and nontyrosinated alpha-tubulin during mitosis.
Distribution of tyrosinated and nontyrosinated alpha-tubulin during mitosis.
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DOI：
10.1083/jcb.102.3.1118
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发表时间：
1986-03
期刊：
影响因子：
--
通讯作者：
Bulinski JC
中科院分区：
文献类型：
--
作者：
Gundersen GG;Bulinski JC
α-微管蛋白的C末端经历可逆的翻译后酪氨酸化/去酪氨酸化。用针对Tyr和Glu微管蛋白C末端的抗体，用免疫荧光法研究了培养细胞有丝分裂过程中酪氨酸(Tyr)和非酪氨酸(Glu)物种的分布。在有丝分裂的各个阶段，Tyr微管蛋白的分布与Glu微管蛋白的分布不同，总体上，Tyr微管蛋白的分布与总微管蛋白的分布相似，而Glu微管蛋白的分布较为有限。谷氨酸存在于半纺锤体纤维中，但在星形纤维中未检测到，仅在末期才出现在带间。通过直接比较Tyr和Glu微管蛋白在两种抗体双重标记的细胞中的分布，证实了这些结果。根据两种抗体在冷处理细胞中的染色模式，获得了Tyr和Glu微管蛋白在每一类半纺锤体纤维(动粒和极)中存在的证据。免疫印迹结果表明，Glu微管蛋白是纺锤体中总微管蛋白中的一小部分，在有丝分裂的各个阶段均未检测到Tyr和Glu微管蛋白的含量变化。这些结果表明，Tyr微管蛋白是有丝分裂纺锤体中的主要物种，并存在于所有类型的纺锤体纤维中，而Glu微管蛋白则少量存在，分布较有限。纺锤体中存在两种生化上截然不同的α-微管蛋白，这可能对纺锤体的功能很重要。
The C-terminus of alpha-tubulin undergoes a reversible posttranslational tyrosination/detyrosination. The distributions of the tyrosinated (Tyr) and nontyrosinated (Glu) species during mitosis of cultured cells have been investigated by immunofluorescence using antibodies directed against the C-terminus of either Tyr or Glu tubulin. The distribution of Tyr tubulin differed from that of Glu tubulin at each stage of mitosis; in general, the distribution of Tyr tubulin was similar to that of total tubulin, whereas Glu tubulin had a more restricted distribution. The Glu species was found in half-spindle fibers but was not detected in astral fibers at any stage and was seen in the interzone only during telophase. These results were confirmed by a direct comparison of the distributions of Tyr and Glu tubulin in cells double-labeled with the two antibodies. Evidence for the occurrence of Tyr and Glu tubulin in each class of half-spindle fibers (kinetochore and polar) was obtained from the staining patterns of the two antibodies in cold-treated cells. Immunoblots of extracts prepared from synchronous mitotic cells showed that Glu tubulin was a minor species of the total tubulin in the spindle; no changes in the amount of either Tyr or Glu tubulin were detected at any stage of mitosis. These results show that Tyr tubulin is the major species in the mitotic spindle and is found in all classes of spindle fibers, whereas Glu tubulin is present in small amounts and shows a more restricted distribution. The presence of two biochemically distinct forms of alpha- tubulin in the spindle may be important for spindle function.