Physical and functional interactions between the prostate suppressor homeoprotein NKX3.1 and serum response factor.
Physical and functional interactions between the prostate suppressor homeoprotein NKX3.1 and serum response factor.
复制标题
DOI：
10.1016/j.jmb.2006.05.064
复制
发表时间：
2006-07
影响因子：
5.6
通讯作者：
J. Ju;J. Maeng;M. Zemedkun;Natalie Ahronovitz;J. W. Mack;J. Ferretti;E. Gelmann;J. Gruschus
中科院分区：
文献类型：
--
作者：
J. Ju;J. Maeng;M. Zemedkun;Natalie Ahronovitz;J. W. Mack;J. Ferretti;E. Gelmann;J. Gruschus
NKX3.1转录因子是NK家族同源结构域蛋白和肿瘤抑制基因，其在前列腺癌的早期阶段是单倍不足和下调的。与其心脏同源物NKX2.5一样，NKX3.1与血清反应因子（SRF）协同作用，激活平滑肌γ-肌动蛋白（SMGA）基因启动子的表达。使用NMR光谱，观察到包含NKX3.1的N-末端区域和同源结构域的构建体中的三个保守基序与SRF的MADS盒结构域相互作用。这些图案相互作用的DNA的情况下，当两种蛋白质结合到SMGA启动子DNA序列。同源域和SRF MADS盒之间没有观察到显着的相互作用。SRF相互作用区域之一是tinman（TN）或enrailed同源性-1基序（EH-1），残基29-35（FLIQDIL），对于其他NK蛋白，它是与阻遏蛋白Groucho相互作用的位点。第二个疏水相互作用区域被命名为SRF相互作用（SI）基序，包括残基99-105（LGSYLLD）。第三个相互作用基序是邻近SI基序的酸性区域，包括残基88-96（ETLAETEPE）。酸性结构域（AD）基序信号还显示在不存在SRF的情况下NKX3.1同源结构域与DNA结合时增强，这与酸性区域与未结合状态下的同源结构域弱相互作用一致。这些线性基序在NKX3.1和SRF的转录相互作用中的重要性通过在SMGA报告基因测定中对NKX3.1表达载体的靶向诱变来证明。这些结果暗示NKX3.1的N-末端区域在调节这种肿瘤抑制因子的转录活性。
The NKX3.1 transcription factor is an NK family homeodomain protein and a tumor suppressor gene that is haploinsufficient and down-regulated in the early phases of prostate cancer. Like its cardiac homolog, NKX2.5, NKX3.1 acts synergistically with serum response factor (SRF) to activate expression from the smooth muscle γ-actin (SMGA) gene promoter. Using NMR spectroscopy, three conserved motifs in a construct containing the N-terminal region and homeodomain of NKX3.1 were observed to interact with the MADS box domain of SRF. These motifs interacted both in the absence of DNA and when both proteins were bound to a SMGA promoter DNA sequence. No significant interaction was seen between the homeodomain and SRF MADS box. One of the SRF-interacting regions was the tinman (TN) or engrailed homology-1 motif (EH-1), residues 29–35 (FLIQDIL), which for other NK proteins is the site of interaction with the repressor protein Groucho. A second hydrophobic interacting region was designated the SRF-interacting (SI) motif and included residues 99–105 (LGSYLLD). A third interacting motif was the acidic region adjacent to the SI motif including residues 88–96 (ETLAETEPE). The acidic domain (AD) motif signals also showed strengthening upon the NKX3.1 homeodomain binding to DNA in the absence of SRF, consistent with the acidic region weakly interacting with the homeodomain in the unbound state. The importance of these linear motifs in the transcriptional interaction of NKX3.1 and SRF was demonstrated by targeted mutagenesis of an NKX3.1 expression vector in a SMGA reporter assay. The results implicate the NKX3.1 N-terminal region in regulation of transcriptional activity of this tumor suppressor.