The NTF2 protein interacts specifically with the FxFG repeat-containing nucleoporins and Ran-GDP to form complexes [50] resulting in the cytoplasmic-nuclear trafficking of Ran [51]. The yeast (Saccharomyces cerevisiae) and Caenorhabditis elegans NTF2 orthology plays crucial roles and ntf2 mutants have significant imperfection in nuclear trafficking [52]. However, the overexpression of NTF2 also hampers the nuclear import of Ran protein in Arabidopsis [53]. Our **data** also showed that the NTF2 domain exists in 44 MKK3 genes from 38 plant species as early in algae and in mosses, pteridophyta as well as seed plants, including previously reported A. thaliana ( Fig. 7a; [53]). Then sequence alignment of NTF2 domain regions of all identified MKK3 exhibited a critical functional Ran-binding site such as aspartic and glutamic residues (Fig. 7b and c). Our results also revealed that the MKK-NTF fusions took place alone in several plants, including both eudicots and monocotyledons. In order to explore the evolutionary relationship all MKK3 fused NTF2 domain together with all NTF2 proteins from Arabidopsis, we performed the phylogenetic analyses which showed that fusions occurred at least three times and referred to homologs of NTF2a/b, NTF2-1 and NTF2-2 (Fig. 7d). In addition, the group B MKKs with NTF2 domain had a recent clades of lineage-specific paralogs, including one members such clades in soybean, B. distachyon and S. italica, respectively, revealing numerous gene duplication events (Fig. 7d).