Role of RGM coreceptors in bone morphogenetic protein signaling.
Role of RGM coreceptors in bone morphogenetic protein signaling.
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DOI：
10.1186/1750-2187-2-4
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发表时间：
2007-07-05
影响因子：
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通讯作者：
Bain G
中科院分区：
文献类型：
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作者：
Halbrooks PJ;Ding R;Wozney JM;Bain G
排斥性引导分子（RGM）蛋白最初被发现在神经元发育中起作用，最近被确定为骨形态发生蛋白（BMP）信号通路的共受体。bmp是tgf - β信号细胞因子超家族的成员，可调节细胞生长和分化的许多方面。在这里，我们研究了RGMa、RGMb和RGMc是否在小鼠成肌细胞C2C12细胞系的BMP和TGFβ信号传导中发挥了必要的作用。这些细胞对BMP有反应，经常用于研究BMP/ tgf - β信号通路。使用siRNA试剂特异性敲除每个RGM蛋白，我们发现RGM共受体是BMP信号传递所必需的，这是两种基于细胞的BMP活性测定所报告的：内源性碱性磷酸酶活性和基于荧光素酶的BMP报告基因测定。使用TGFβ诱导的荧光素酶报告基因的类似细胞实验表明，RGM共受体不是TGFβ信号转导所必需的。观察和量化了每个RGM共受体与BMP2和BMP12的结合相互作用，并报道了低纳摩尔范围内的平衡解离常数。我们的研究结果表明，RGMs在BMP信号传导中起着重要作用，并揭示了这些分子在功能上不能相互补偿。
The repulsive guidance molecule (RGM) proteins, originally discovered for their roles in neuronal development, have been recently identified as co-receptors in the bone morphogenetic protein (BMP) signaling pathway. BMPs are members of the TGFβ superfamily of signaling cytokines, and serve to regulate many aspects of cellular growth and differentiation. Here, we investigate whether RGMa, RGMb, and RGMc play required roles in BMP and TGFβ signaling in the mouse myoblast C2C12 cell line. These cells are responsive to BMPs and are frequently used to study BMP/TGFβ signaling pathways. Using siRNA reagents to specifically knock down each RGM protein, we show that the RGM co-receptors are required for significant BMP signaling as reported by two cell-based BMP activity assays: endogenous alkaline phosphatase activity and a luciferase-based BMP reporter assay. Similar cell-based assays using a TGFβ-induced luciferase reporter show that the RGM co-receptors are not required for TGFβ signaling. The binding interaction of each RGM co-receptor to each of BMP2 and BMP12 is observed and quantified, and equilibrium dissociation constants in the low nanomolar range are reported. Our results demonstrate that the RGMs play a significant role in BMP signaling and reveal that these molecules cannot functionally compensate for one another.