Regulation of tension-induced mechanotranscriptional signals by the microtubule network in fibroblasts
Regulation of tension-induced mechanotranscriptional signals by the microtubule network in fibroblasts
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DOI：
10.1074/jbc.m309027200
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发表时间：
2003-12-26
影响因子：
4.8
通讯作者：
McCulloch, CAG
中科院分区：
文献类型：
--
作者：
D'Addario, M;Arora, PD;McCulloch, CAG
结缔组织的机械负荷诱导参与基质重塑的细胞外基质和细胞骨架基因的表达。这些过程部分取决于通过β（1）整合素和肌动蛋白丝的力传递，但微管在调节机械转录反应中的作用尚不清楚。我们评估了微管在细丝蛋白 A 的机械转录调节中的作用，细丝蛋白 A 是一种肌动蛋白交联蛋白，通过稳定细胞膜来保护细胞免受力诱导的细胞凋亡。使用胶原蛋白包被的磁铁矿珠和磁场对粘着斑处培养的成纤维细胞施加拉力。强制增强 α-微管蛋白和正端微管结合蛋白细胞质连接蛋白 170 (CLIP-170) 在粘着斑处的募集。免疫沉淀研究表明微管蛋白与肌动蛋白或细丝蛋白 A 没有直接结合，但 CLIP-170 与微管蛋白、细丝蛋白 A 和 β-肌动蛋白相互作用。 CLIP-170 与 β-肌动蛋白的结合通过强制增强。力激活 p38 丝裂原激活蛋白激酶，增加细丝蛋白 A 表达，并诱导 p38 和细丝蛋白 A 重新定位至粘着斑。用诺考达唑破坏微管，与施加力无关，增强细丝蛋白 A 表达和 Sp1 介导的细丝蛋白 A 启动子活性，而用紫杉醇稳定微管则抑制细丝蛋白 A mRNA 和蛋白质的力诱导。我们得出的结论是，响应通过 β(1) 整联蛋白和肌动蛋白施加的张力，微管网络调节细丝蛋白 A 的机械转录耦合。
Mechanical loading of connective tissues induces the expression of extracellular matrix and cytoskeletal genes that are involved in matrix remodeling. These processes depend in part on force transmission through beta(1) integrins and actin filaments, but the role of microtubules in regulating mechanotranscriptional responses is not well defined. We assessed the involvement of microtubules in the mechanotranscriptional regulation of filamin A, an actin-cross-linking protein that protects cells against force-induced apoptosis by stabilizing cell membranes. Collagen-coated magnetite beads and magnetic fields were used to apply tensile forces to cultured fibroblasts at focal adhesions. Force enhanced recruitment of alpha-tubulin and the plus end microtubule-binding protein cytoplasmic linker protein-170 (CLIP-170) at focal adhesions. Immunoprecipitation studies demonstrated no direct binding of tubulin to actin or filamin A, but CLIP-170 interacted with tubulin, filamin A, and beta-actin. The association of CLIP-170 with beta-actin was enhanced by force. Force activated the p38 mitogen-activated protein kinase, increased filamin A expression, and induced the relocation of p38 and filamin A to focal adhesions. Disruption of microtubules with nocodazole, independent of force application, enhanced filamin A expression and Sp1-mediated filamin A promoter activity, while stabilization of microtubules with Taxol inhibited force induction of both filamin A mRNA and protein. We conclude that in response to tensile forces applied through beta(1) integrins and actin the microtubule network modulates mechanotranscriptional coupling of filamin A.