Transcription factor that specifically binds AT-rich DNA sequences related to the nuclear matrix attachment regions (MARs) (By similarity). Acts redundantly with AHL3 to regulate the formation of tissue boundary between the xylem and procambium in the root meristem. Cell-to-cell movement of AHL4 from the procambium to the xylem is critical for its function in root vascular patterning (PubMed:23335615). Homodimer. Interacts with AHL3. Predominantly expressed in the stele of the root meristem with a specificity to the procambium. The PPC domain mediates interactions between AHL proteins. Misspecification of tissue boundaries between the xylem and procambium.