Association of mitogen-activated protein kinases with microtubules in mouse macrophages.
Association of mitogen-activated protein kinases with microtubules in mouse macrophages.
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DOI：
10.1084/jem.183.4.1899
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发表时间：
1996-04-01
期刊：
影响因子：
--
通讯作者：
Blum E
中科院分区：
文献类型：
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作者：
Ding A;Chen B;Fuortes M;Blum E
紫杉醇是一种微管结合型二萜类化合物，可模拟脂多糖（LPS）对小鼠巨噬细胞的许多作用。紫杉醇的LPS模拟效应似乎与对LPS本身的反应处于相同的遗传控制之下。因此，我们假设微管相关蛋白（MAP）在巨噬细胞对LPS的反应中起作用。LPS对巨噬细胞的刺激可迅速诱导丝裂原活化蛋白激酶（MAPK）的活化。MAPK通常被认为是胞质酶。在此，我们报告，大部分的LPS激活池的MAPK在原代小鼠腹腔巨噬细胞微管相关。通过免疫荧光，MAPK被定位于秋水仙素和诺考达唑可破坏的丝。从小鼠脑和RAW 264.7巨噬细胞中，MAPK可以与聚合的微管蛋白共分离。将原代巨噬细胞分成胞质溶胶、微丝、微管和中间体，富含活性物质的提取物，发现约10%的MAPK但没有MAPK激酶（MEK1A和MEK2）被微管结合。巨噬细胞暴露于LPS并不改变与微管结合的MAPK的比例，但优先激活微管相关池。这些发现证实了LPS激活与微管结合的激酶的预测。与LPS模拟行动的紫杉醇和共享的遗传控制的LPS和紫杉醇的反应，这些结果支持的假设，在小鼠巨噬细胞中的一个主要的LPS信号通路可能涉及激活一个或多个微管相关激酶。
Taxol, a microtubule-binding diterpene, mimics many effects of lipopolysaccharide (LPS) on mouse macrophages. The LPS-mimetic effects of taxol appear to be under the same genetic control as responses to LPS itself. Thus we have postulated a role for microtubule-associated proteins (MAP) in the response of macrophages to LPS. Stimulation of macrophages by LPS quickly induces the activation of mitogen-activated protein kinases (MAPK). MAPK are generally considered cytosolic enzymes. Herein we report that much of the LPS-activatable pool of MAPK in primary mouse peritoneal macrophages is microtubule associated. By immunofluorescence, MAPK were localized to colchicine- and nocodazole- disruptible filaments. From both mouse brain and RAW 264.7 macrophages, MAPK could be coisolated with polymerized tubulin. Fractionation of primary macrophages into cytosol-, microfilament-, microtubule-, and intermediated filament-rich extracts revealed that approximately 10% of MAPK but none of MAPK kinase (MEK1A and MEK2) was microtubule bound. Exposure of macrophages to LPS did not change the proportion of MAPK bound to microtubules, but preferentially activated the microtubule- associated pool. These findings confirm the prediction that LPS activates a kinase bound to microtubules. Together with LPS-mimetic actions of taxol and the shared genetic control of responses to LPS and taxol, these results support the hypothesis that a major LPS-signaling pathway in mouse macrophages may involve activation of one or more microtubule-associated kinases.