Tropomyosin isoforms define distinct microfilament populations with different drug susceptibility
Tropomyosin isoforms define distinct microfilament populations with different drug susceptibility
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DOI：
10.1016/j.ejcb.2008.03.004
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发表时间：
2008-09-01
影响因子：
6.6
通讯作者：
Gunning, Peter
中科院分区：
文献类型：
--
作者：
Creed, Sarah J.;Bryce, Nicole;Gunning, Peter
两种原肌球蛋白亚型人TM5(NM1)和TM3在B35大鼠神经上皮细胞中过表达，以研究特定的肌动蛋白和原肌球蛋白亚型之间的优势联系，并确定原肌球蛋白亚型在调节肌动蛋白细丝群体的药物敏感性中所起的作用。免疫荧光染色和Western印迹分析用于研究特定细丝群体的组织以及它们对两种广泛使用的破坏肌动蛋白稳定的药物--Latrunculin A和细胞松弛素D处理的反应。在TM5(NM1)细胞中，我们观察到大的应力纤维，显示出主要的β-肌动蛋白和低分子γ-原肌球蛋白亚型的共同定位。TM3细胞有丰富的细胞突起，包含β-和γ-肌动蛋白亚型，主要由高分子质量的α-和β-原肌球蛋白亚型组成。在TM5(NM1)细胞中观察到的应力纤维比在TM3细胞中观察到的含有高相对分子质量原肌球蛋白的细丝更能抵抗TM5(NM1)细胞中观察到的棒状菌素A和细胞松弛素D。用人特有的TM5(NM1)siRNA敲除过表达的TM5(NM1)异构体，逆转了表型，并导致了观察到的耐药性的逆转。我们的结论是，特定的肌动蛋白和原肌球蛋白亚型之间存在优先关联，这是细胞类型特有的，但细丝群体的原肌球蛋白组成决定了对肌动蛋白靶向药物的敏感性。(C)2008年爱思唯尔股份有限公司。版权所有。
Two tropomyosin isoforms, human Tm5(NM1) and Tm3, were over-expressed in B35 rat neuro-epithelial cells to examine preferential associations between specific actin and tropomyosin isoforms and to determine the role tropomyosin isoforms play in regulating the drug Susceptibility of actin filament populations. Immunofluorescence staining and Western blot analysis were used to Study the organisation of specific filament populations and their response to treatment with two widely used actin-destabilising drugs, latrunculin A and cytochalasin D. In Tm5(NM1) cells, we observed large stress fibres which showed predominant co-localisation of beta-actin and low-molecular-weight gamma-tropomyosin isoforms. Tm3 cells had an abundance of cellular protrusions which contained both the beta- and gamma-actin isoforms, predominately populated by high-molecular-weight alpha- and beta-tropomyosin isoforms. The stress fibres observed in Tm5(NM1) cells were more resistant to both latrunculin A and cytochalasin D than filaments containing the high-molecular-weight tropomyosins observed in Tm3 cells. Knockdown of the over-expressed Tm5(NM1) isoform with a human-specific Tm5(NM1) siRNA reversed the phenotype and caused a reversal in the observed drug resistance. We conclude that there are preferential associations between specific actin and tropomyosin isoforms, which are cell type specific, but it is the tropomyosin composition of a filament Population which determines the susceptibility to actin-targeting drugs. (C) 2008 Elsevier GmbH. All rights reserved.