Extracellular signal-regulated kinase 2 interacts with and is negatively regulated by the LIM-only protein FHL2 in cardiomyocytes
Extracellular signal-regulated kinase 2 interacts with and is negatively regulated by the LIM-only protein FHL2 in cardiomyocytes
复制标题
DOI：
10.1128/mcb.24.3.1081-1095.2004
复制
发表时间：
2004-02-01
影响因子：
5.3
通讯作者：
Molkentin, JD
中科院分区：
文献类型：
--
作者：
Purcell, NH;Darwis, D;Molkentin, JD
丝裂原活化蛋白激酶（MAPK）信号通路调节多种生物学功能，包括细胞生长、分化、增殖和凋亡。细胞外信号调节激酶（ERK）构成MAPK通路的一个分支，该通路参与心脏分化生长的调节，尽管ERK信号传导影响这一过程的下游机制还没有很好地表征。在这里，我们进行了酵母双杂交筛选与ERK 2诱饵和心脏cDNA文库，以确定新的蛋白参与调节ERK信号在心肌细胞。该筛选鉴定了在酵母和哺乳动物细胞中作为ERK相互作用蛋白的仅LIM因子FHL 2。在体内，FHL 2和ERK 2共定位于细胞质中的Z线水平，有趣的是，FHL 2与ERK 2的活化形式比与去磷酸化形式更有效地相互作用。ERK 2也与FHL 1和FHL 3相互作用，但不与肌肉LIM蛋白相互作用。此外，FHL 2中至少需要两个LIM结构域来介导与ERK 2的有效相互作用。ERK 2和FHL 2之间的相互作用不影响ERK 1/2的激活，也不直接磷酸化FHL 2的ERK 2。然而，FHL 2抑制了活化的ERK 2驻留在细胞核内的能力，从而阻断了ELK-1、GATA 4和心房利钠因子启动子的ERK依赖性转录反应。最后，FHL 2部分拮抗由活化的MEK-1、GATA 4和苯肾上腺素激动剂刺激诱导的心脏肥大反应。总的来说，这些结果表明，FHL 2通过其抑制ERK 1/2转录偶联的能力在心肌细胞中发挥阻遏物功能。
The mitogen-activated protein kinase (MAPK) signaling pathway regulates diverse biologic functions including cell growth, differentiation, proliferation, and apoptosis. The extracellular signal-regulated kinases (ERKs) constitute one branch of the MAPK pathway that has been implicated in the regulation of cardiac differentiated growth, although the downstream mechanisms whereby ERK signaling affects this process are not well characterized. Here we performed a yeast two-hybrid screen with ERK2 bait and a cardiac cDNA library to identify novel proteins involved in regulating ERK signaling in cardiomyocytes. This screen identified the LIM-only factor FHL2 as an ERK interacting protein in both yeast and mammalian cells. In vivo, FHL2 and ERK2 colocalized in the cytoplasm at the level of the Z-line, and interestingly, FHL2 interacted more efficiently with the activated form of ERK2 than with the dephosphorylated form. ERK2 also interacted with FHL1 and FHL3 but not with the muscle LIM protein. Moreover, at least two LIM domains in FHL2 were required to mediate efficient interaction with ERK2. The interaction between ERK2 and FHL2 did not influence ERK1/2 activation, nor was FHL2 directly phosphorylated by ERK2. However, FHL2 inhibited the ability of activated ERK2 to reside within the nucleus, thus blocking ERK-dependent transcriptional responsiveness of ELK-1, GATA4, and the atrial natriuretic factor promoter. Finally, FHL2 partially antagonized the cardiac hypertrophic response induced by activated MEK-1, GATA4, and phenylephrine agonist stimulation. Collectively, these results suggest that FHL2 serves a repressor function in cardiomyocytes through its ability to inhibit ERK1/2 transcriptional coupling.