Necdin interacts with the Msx2 homeodomain protein via MAGE-D1 to promote myogenic differentiation of C2C12 cells
Necdin interacts with the Msx2 homeodomain protein via MAGE-D1 to promote myogenic differentiation of C2C12 cells
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DOI：
10.1074/jbc.m404143200
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发表时间：
2004-09-24
影响因子：
4.8
通讯作者：
Yoshikawa, K
中科院分区：
文献类型：
--
作者：
Kuwajima, T;Taniura, H;Yoshikawa, K
Necdin是一种有效的生长抑制因子，主要在有丝分裂后细胞如神经元和骨骼肌细胞中表达。Necdin显示与法师（黑素瘤抗原）家族蛋白的显著同源性，所有这些家族蛋白都含有大的同源结构域。MAGE-D1（Nembryos，Dlxin-1）通过与同源结构域不同的散布的六肽重复结构域与Dlx/Msx家族同源结构域蛋白相互作用。在这里，我们报告necdin协会与Msx同源结构域蛋白通过MAGE-D1调节其功能。体外结合和免疫共沉淀分析表明，MAGE-D1直接相互作用necdin通过同源结构域和Msx 1（或Msx 2）通过重复结构域。necdin，MAGE-D1和Msx 2的三元复合物在体外形成，并检测到含有这三种蛋白质的内源性复合物在分化的胚胎癌细胞。necdin和MAGE-D1的共表达释放Msx依赖的转录抑制。稳定转染Msx 2 cDNA的C2 C12成肌细胞成肌分化明显减少，necdin和MAGE-D1的共表达取消了Msx 2依赖性抑制。这些结果表明，necdin和MAGE-D1合作，以调节Dlx/Msx同源结构域蛋白在细胞分化中的功能。
Necdin is a potent growth suppressor that is expressed predominantly in postmitotic cells such as neurons and skeletal muscle cells. Necdin shows a significant homology to MAGE (melanoma antigen) family proteins, all of which contain a large homology domain. MAGE-D1 (NRAGE, Dlxin-1) interacts with the Dlx/Msx family homeodomain proteins via an interspersed hexapeptide repeat domain distinct from the homology domain. Here we report that necdin associates with the Msx homeodomain proteins via MAGE-D1 to modulate their function. In vitro binding and co-immunoprecipitation analyses revealed that MAGE-D1 directly interacted with necdin via the homology domain and Msx1 (or Msx2) via the repeat domain. A ternary complex of necdin, MAGE-D1, and Msx2 was formed in vitro, and an endogenous complex containing these three proteins was detected in differentiating embryonal carcinoma cells. Co-expression of necdin and MAGE-D1 released Msx-dependent transcriptional repression. C2C12 myoblast cells that were stably transfected with Msx2 cDNA showed a marked reduction in myogenic differentiation, and co-expression of necdin and MAGE-D1 canceled the Msx2-dependent repression. These results suggest that necdin and MAGE-D1 cooperate to modulate the function of Dlx/Msx homeodomain proteins in cellular differentiation.