Taxol binds to cellular microtubules.
Taxol binds to cellular microtubules.
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DOI：
10.1083/jcb.94.3.688
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发表时间：
1982-09
期刊：
影响因子：
--
通讯作者：
Horwitz SB
中科院分区：
文献类型：
--
作者：
Manfredi JJ;Parness J;Horwitz SB
紫杉醇是一种低分子量的植物衍生物，其在体外增强微管组装，并且具有促进细胞中离散微管束形成的独特能力。氚标记的紫杉醇在体外以接近1的化学计量直接与微管结合（Parness，J.，和S. B。Horwitz，1981，J. Cell Biol.91：479-487）。我们现在报告的研究，在细胞中的结合[3 H]紫杉醇和微管束的形成。[3 H]紫杉醇以特异性和饱和性方式与巨噬细胞样细胞系J774.2结合。特异性结合数据的Scatchard分析证明了一组高亲和力结合位点。在产生最大生长抑制的药物浓度下发生最大结合。通过微管蛋白免疫荧光测定，在完整和提取的细胞中使微管去活化的条件抑制[3 H]紫杉醇的结合。这有力地表明紫杉醇特异性结合细胞微管。用0.1% Nonidet P-40提取或用10 mM NaN 3处理细胞ATP耗竭可防止特征性紫杉醇诱导的束形成。然而，在这些条件下保留了[3 H]紫杉醇的结合。因此，有形成。然而，在这些条件下保留了[3 H]紫杉醇的结合。因此，除了紫杉醇与细胞质微管的直接结合之外，还必须有特定的细胞机制来形成束。
Taxol is a low molecular weight plant derivative which enhances microtubule assembly in vitro and has the unique ability to promote the formation of discrete microtubule bundles in cells. Tritium-labeled taxol binds directly to microtubules in vitro with a stoichiometry approaching one (Parness, J., and S. B. Horwitz, 1981, J. Cell Biol. 91:479-487). We now report studies in cells on the binding of [3H]taxol and the formation of microtubule bundles. [3H]Taxol binds to the macrophagelike cell line, J774.2, in a specific and saturable manner. Scatchard analysis of the specific binding data demonstrates a single set of high affinity binding sites. Maximal binding occurs at drug concentrations which produce maximal growth inhibition. Conditions which depolymerize microtubules in intact and extracted cells as determined by tubulin immunofluorescence inhibit the binding of [3H]taxol. This strongly suggests that taxol binds specifically to cellular microtubules. Extraction with 0.1% Nonidet P-40 or depletion of cellular ATP by treatment with 10 mM NaN3 prevents the characteristic taxol-induced bundle formation. The binding of [3H]taxol, however, is retained under these conditions. Thus, there formation. The binding of [3H]taxol, however, is retained under these conditions. Thus, there must be specific cellular mechanisms which are required for bundle formation, in addition to the direct binding of taxol to cytoplasmic microtubules.