Transcription factor. Homodimer. Interacts with BZIP1, BZIP2, BZIP10, BZIP11, BZIP25, BZIP44, BZIP53 and BZIP63. Expressed in roots, shoots, stems, young leaves, and flowers, mostly in vascular tissues (e.g. phloem). Present in silique vasculature and funiculi. In the anthers, restricted to the connective tissue at pre- and post-dehiscence stages and detected in the vascular tissue of the stamen filament. Repressed by glucose. Phosphorylated. Belongs to the bZIP family.