Cai Xin, Wang Jinfeng, Huang Xin, Fu Wenliang, Xia Wenrong, Zou Minji, Wang Yuanyuan, Wang Jiaxi, Xu Donggang
Laboratory of Genome Engineering, Beijing Institute of Basic Medical Sciences, Beijing, PR China.
PLoS One. 2014 Apr 1;9(4):e93723. doi: 10.1371/journal.pone.0093723. eCollection 2014.
Four and a half LIM domain protein 3 (FHL3) is a member of the FHL protein family that plays roles in the regulation of cell survival, cell adhesion and signal transduction. However, the mechanism of action for FHL3 is not yet clear. The aim of present study was to identify novel binding partner of FHL3 and to explore the underlying mechanism. With the use of yeast two-hybrid screening system, FHL3 was used as the bait to screen human fetal hepatic cDNA library for interacting proteins. Methionine-1X was identified as a novel FHL3 binding partner. The interaction between FHL3 and the full length MT-1X was further confirmed by yeast two-hybrid assay, co-immunoprecipitation and GST pull-down assays. Furthermore,the result demonstrated that MT-1X knockdown promoted the FHL3-induced inhibitory effect on HepG2 cells by regulating FHL3-mediated Smad signaling and involving in the modulation the expression of G2/M phase-related proteins through interaction with FHL3. These findings suggest that functional interactions between FHL3 and MT-1X may provide some clues to the mechanisms of FHL3-regulated cell proliferation.
四和半LIM结构域蛋白3（FHL3）是FHL蛋白家族的成员，在细胞存活、细胞黏附和信号转导的调节中发挥作用。然而，FHL3的作用机制尚不清楚。本研究的目的是鉴定FHL3的新型结合伴侣并探索其潜在机制。利用酵母双杂交筛选系统，以FHL3作为诱饵筛选人胎儿肝脏cDNA文库中的相互作用蛋白。甲硫氨酸-1X（MT-1X）被鉴定为FHL3的新型结合伴侣。通过酵母双杂交试验、免疫共沉淀和GST下拉试验进一步证实了FHL3与全长MT-1X之间的相互作用。此外，结果表明，MT-1X敲低通过调节FHL3介导的Smad信号传导并通过与FHL3相互作用参与调节G2/M期相关蛋白的表达，从而促进FHL3对HepG2细胞的抑制作用。这些发现表明，FHL3与MT-1X之间的功能相互作用可能为FHL3调节细胞增殖的机制提供一些线索。
