University of Wroclaw, Institute of Experimental Biology, Department of Plant Molecular Physiology, Kanonia, Wroclaw, Poland.
University of Wroclaw, Institute of Experimental Biology, Department of Genetics and Cell Physiology, Kanonia, Wroclaw, Poland.
J Exp Bot. 2019 Jan 1;70(1):285-300. doi: 10.1093/jxb/ery342.
Members of the cation diffusion facilitator (CDF) family have been identified in all kingdoms of life. They have been divided into three subgroups, namely Zn-CDF, Fe/Zn-CDF, and Mn-CDF, based on their putative specificity to transported metal ions. The plant metal tolerance protein 6 (MTP6) proteins fall into the Fe/Zn-CDF subgroup; however, their function in iron/zinc transport has not yet been confirmed. Here, we characterized the MTP6 protein from cucumber, Cucumis sativus. When expressed in yeast and in protoplasts isolated from Arabidopsis cells, CsMTP6 localized in mitochondria and contributed to the efflux of Fe and Mn from these organelles. Immunolocalization of CsMTP6 in cucumber membranes confirmed this association with mitochondria. Root expression and protein levels of CsMTP6 were significantly up-regulated in conditions of Fe deficiency and excess, but were not affected by Mn availability. These results indicate that MTP6 proteins contribute to the distribution of Fe and Mn between the cytosol and mitochondria of plant cells, and are regulated by Fe to maintain mitochondrial and cytosolic iron homeostasis under varying conditions of Fe availability.
阳离子扩散促进因子（CDF）家族的成员已在所有生命领域中被鉴定出来。它们根据其推测的运输金属离子的特异性分为三个亚群，即 Zn-CDF、Fe/Zn-CDF 和 Mn-CDF。植物金属耐受蛋白 6（MTP6）蛋白属于 Fe/Zn-CDF 亚群；然而，其在铁/锌转运中的功能尚未得到证实。在这里，我们对黄瓜中的 MTP6 蛋白进行了表征。当在酵母和拟南芥细胞原生质体中表达时，CsMTP6 定位于线粒体，并有助于这些细胞器中铁和锰的外排。在黄瓜膜中的 CsMTP6 的免疫定位证实了与线粒体的这种关联。在缺铁和过量的条件下，CsMTP6 的根表达和蛋白水平显著上调，但不受 Mn 供应的影响。这些结果表明，MTP6 蛋白有助于铁和锰在植物细胞的细胞质和线粒体之间的分布，并受铁的调节，以在不同的铁供应条件下维持线粒体和细胞质的铁稳态。
