Protein stability and function of p73 are modulated by a physical interaction with RanBPM in mammalian cultured cells
Protein stability and function of p73 are modulated by a physical interaction with RanBPM in mammalian cultured cells
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DOI：
10.1038/sj.onc.1208257
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发表时间：
2005-01-27
期刊：
影响因子：
8
通讯作者：
Nakagawara, A
中科院分区：
文献类型：
--
作者：
Kramer, S;Ozaki, T;Nakagawara, A
在一定的DNA损伤，包括顺铂治疗，p73是稳定的，并发挥其生长抑制和/或促凋亡功能。然而，细胞内p73水平调节的精确分子基础仍不清楚。在本研究中，我们已经确定RanBPM作为一个新的结合伙伴的p73 α的酵母为基础的双杂交筛选，也发现RanBPM具有稳定p73 α的能力。GST下拉分析和免疫共沉淀实验表明，RanBPM直接绑定到极端的COOH末端区域的p73 α，而它未能与p53相互作用。RanBPM与p73 α的共表达导致RanBPM的核转位，并且通过间接免疫荧光染色检测，这两种蛋白质共定位于细胞核中。值得注意的是，RanBPM的表达抑制了p73 alpha的遍在化，从而延长了其半衰期。随后的研究表明，在RanBPM的存在下，p73 α的促凋亡活性显著增强。总之，我们目前的研究结果暗示了RanBPM在调节p73稳定性和功能中的新作用。
Upon a certain DNA damage including cisplatin treatment, p73 is stabilized and exerts its growth-suppressive and/or proapoptotic function. However, the precise molecular basis by which the intracellular levels of p73 are regulated remains unclear. In the present study, we have identified RanBPM as a novel binding partner of p73alpha by yeast-based two-hybrid screening, and also found that RanBPM has an ability to stabilize p73alpha. GST pull-down assays and co-immunoprecipitation experiments revealed that RanBPM directly bound to the extreme COOH-terminal region of p73alpha, whereas it failed to interact with p53. Co-expression of RanBPM with p73alpha resulted in the nuclear translocation of RanBPM, and both proteins co-localized in cell nucleus as examined by indirect immunofluorescent staining. It is worth noting that the expression of RanBPM inhibited the ubiquitination of p73alpha, and thereby prolonged its half-life. Subsequent studies demonstrated that the proapoptotic activity of p73alpha was significantly enhanced in the presence of RanBPM. Taken together, our present findings implicate a novel role for RanBPM in the regulation of p73 stability and function.