Department of Biological Chemistry, John Innes Centre, Norwich Research Park Norwich, UK.
Front Plant Sci. 2013 May 21;4:149. doi: 10.3389/fpls.2013.00149. eCollection 2013.
Nuclear translocation of immune regulatory proteins and signal transducers is an essential process in animal and plant defense signaling against pathogenic microbes. Import of proteins containing a nuclear localization signal (NLS) into the nucleus is mediated by nuclear transport receptors termed importins, typically dimers of a cargo-binding α-subunit and a β-subunit that mediates translocation through the nuclear pore complex. Here, we review recent reports of importin-α cargo specificity and mutant phenotypes in plant- and animal-microbe interactions. Using homology modeling of the NLS-binding cleft of nine predicted Arabidopsis α-importins and analyses of their gene expression patterns, we discuss functional redundancy and specialization within this transport receptor family. In addition, we consider how pathogen effector proteins that promote infection by manipulating host cell nuclear processes might compete with endogenous cargo proteins for nuclear uptake.
免疫调节蛋白和信号转导因子的核转位是动植物防御信号对抗病原微生物的一个重要过程。含有核定位信号（NLS）的蛋白质的核输入是由核转运受体介导的，这些受体通常是货物结合α亚基和β亚基的二聚体，通过核孔复合体介导转运。在这里，我们综述了最近关于植物-微生物和动物-微生物相互作用中α-importin 货物特异性和突变表型的报告。我们利用九个预测的拟南芥α-importin 的 NLS 结合裂缝的同源建模和它们的基因表达模式分析，讨论了这个转运受体家族中的功能冗余和专业化。此外，我们还考虑了如何通过操纵宿主细胞的核过程来促进感染的病原体效应蛋白可能与内源性货物蛋白竞争核摄取。
