RHO methylation matters A role for isoprenylcysteine carboxylmethyltransferase in cell migration and adhesion
RHO methylation matters A role for isoprenylcysteine carboxylmethyltransferase in cell migration and adhesion
复制标题
DOI：
10.4161/cam.5.1.13196
复制
发表时间：
2011-01-01
影响因子：
3.2
通讯作者：
Casey, Patrick J.
中科院分区：
文献类型：
--
作者：
Cushman, Ian;Casey, Patrick J.
许多蛋白质参与细胞生物学的不同方面经历翻译后修饰的过程称为前酰化。戊烯酰化途径包括三个酶促步骤，最后一个步骤是前两个步骤中由异戊烯酰半胱氨酸羧甲基转移酶（Icmt）形成的羧基末端戊烯酰半胱氨酸甲基化。由于preylated蛋白在癌症生物学中的普遍存在，以及一些蛋白参与控制细胞迁移和粘附过程的发现，我们试图研究icmt介导的甲基化在与转移相关的细胞行为中的作用。我们发现抑制甲基化可减少高转移性MDA-MB-231乳腺癌细胞系的迁移。此外，Icmt抑制还能抑制细胞粘附和细胞扩散。进一步的研究表明，Icmt的抑制显著降低了RhoA和Rac1的激活，这两种蛋白都是戊基化蛋白。获得的数据与活性降低是一致的，因为在没有甲基化的情况下，两种蛋白质结合的Rho gdp -解离抑制剂（GDI）增加。重要的是，在Icmt被抑制的细胞中添加外源性RhoA或Rac1分别能够部分但选择性地挽救定向和随机迁移。这些结果确定了icmt介导的甲基化在细胞迁移中的作用，并指出了参与这一生物学过程的特异性烯丙基化蛋白。戊烯酰化途径已被定位为致癌途径，但甲基化在细胞运动中的作用迄今尚未被广泛探索。Rho家族成员的甲基化影响其功能的特定组成部分的发现为研究这类重要调节蛋白的生物学提供了额外的途径。
Numerous proteins involved in diverse aspects of cell biology undergo a process of post-translational modification termed prenylation. The prenylation pathway consists of three enzymatic steps, the final of which is methylation of the carboxyl-terminal prenylcysteine formed in the first two steps by the enzyme isoprenylcysteine carboxylmethyltransferase (Icmt). Due to the prevalence of prenylated proteins in cancer biology and the findings that several of the proteins are involved in processes controlling cell migration and adhesion, we sought to examine the role of Icmt-mediated methylation on cell behavior associated with metastasis. We found that inhibition of methylation reduces migration of the highly metastatic MDA-MB-231 breast cancer cell line. In addition, cell adhesion and cell spreading were also impaired by Icmt inhibition. Further investigation revealed that inhibition of Icmt significantly decreased the activation of both RhoA and Rac1, which are both prenylated proteins. The data obtained were consistent with the decreased activation being due to an increase in Rho GDP-dissociation inhibitor (GDI) binding by both proteins in the absence of their methylation. Importantly, the addition of exogenous RhoA or Rac1 to cells in which Icmt was inhibited was able to partially, but selectively, rescue directed and random migration, respectively. These results establish a role for Icmt-mediated methylation in cell migration, and point to specific prenylated proteins involved in this biology. The prenylation pathway has been targeted for oncogenic but the role of methylation in cell motility had been largely unexplored until now. The finding that methylation of Rho family members impacts on a specific component of their function provides an additional avenue through which to interrogate the biology of this important class of regulatory proteins.