Selective localization of PCBP2 to cytoplasmic processing bodies
Selective localization of PCBP2 to cytoplasmic processing bodies
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DOI：
10.1016/j.bbamcr.2009.02.002
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发表时间：
2009-05-01
影响因子：
5.1
通讯作者：
Murata, Masayuki
中科院分区：
文献类型：
--
作者：
Fujimura, Ken;Katahira, Jun;Murata, Masayuki
加工小体(P小体)是参与基因表达调控的关键步骤的细胞质结构域，包括mRNA衰变和转录后基因沉默。先前，我们报道了PCBP2(Poly-(RC)Binding Protein 2，多聚(RC)结合蛋白2)，它是IRES介导的翻译的促进剂，是一个新的P体成分。有趣的是，PCBP2只招募到Dcp1a阳性P小体的一个子集，这可能反映了这些结构中功能的多样性。在本研究中，我们详细研究了PCBP2的选择性P小体定位。Dcp1a和PCBP2的共定位研究表明，PCBP2存在于大约40%的P小体中。虽然PCBP2更有可能存在于较大的P小体中，但P小体的大小似乎不是唯一的决定因素，而且扑红霉素诱导的P小体的增大只是轻微地增加了PCBP2阳性的P小体的百分比。光漂白实验表明，PCBP2在特定的P小体上的积累是一个动态过程，与蛋白质转录依赖的核质穿梭活动无关。最后，我们发现PCBP2的近亲PCBP1以与PCBP2相似的方式定位于P小体。综上所述，这些结果证实了P小体之间的组成多样性，并且PCBP2可能与其他mRNP因子一起复杂，可能动态地识别这种差异并积累到特定的P小体上。(C)2009爱思唯尔B.V.保留所有权利。
Processing bodies (P-bodies) are cytoplasmic domains that have been implicated in critical steps of the regulation of gene expression, including mRNA decay and post-transcriptional gene silencing. Previously, we reported that PCBP2 (Poly-(rC) Binding Protein 2), a facilitator of IRES-mediated translation, is a novel P-body component. Interestingly, PCBP2 is recruited to only a subset of Dcp1a-positive P-bodies, which may reflect functional diversity among these structures. In this study, we examined the selective P-body localization of PCBP2 in detail. Co-localization studies between Dcp1a and PCBP2 revealed that PCBP2 is present in similar to 40% of P-bodies. While PCBP2 was more likely to reside in larger P-bodies, P-body size did not seem to be the sole determinant, and puromycin-induced enlargement of P-bodies only modestly increased the percentage of PCBP2-positive P-bodies. Photobleaching experiments demonstrated that the accumulation of PCBP2 to specific P-bodies is a dynamic process, which does not involve the protein's transcription-dependent nucleo-cytoplasmic shuttling activity. Finally, we found that PCBP1, a close relative of PCBP2, localizes to P-bodies in a similar manner to PCBP2. Taken together, these results establish the compositional diversity among P-bodies, and that PCBP2, probably in complex with other mRNP factors, may dynamically recognize such differences and accumulate to specific P-bodies. (C) 2009 Elsevier B.V. All rights reserved.