Dual targeting of HXK to mitochondria and plastids. A, Phylogenetic analysis of genes encoding HXK from Arabidopsis (At), Rice (Os), P. glauca (Pg), P. patens (Pp), C. reinhardtii (Cr), and C. variabilis (Cv) using MEGA 5 (see “Materials and Methods”). B, Table of the HXK proteins from Arabidopsis, rice, P. glauca, P. patens, C. reinhardtii, and C. variabilis with genomic loci numbers, targeting predictions, and experimental localization based on GFP tagging. C, GFP tagging of several HXK proteins from Arabidopsis showed that no dual targeting was evident for any HXK protein in Arabidopsis. D and E, GFP tagging of several HXK proteins from P. patens revealed that PpHXK2, PpHXK3, PpHXK5, PpHXK7, PpHXK9, and PpHXK11 displayed dual-targeting ability. Mitochondria (M) and plastids (Pl) are indicated respectively. Scale bar indicates 20 µm. Cyto, Cytosol; ER, endoplasmic reticulum; EX, extracellular; S, secretory pathway.