HKD domains are essential for catalysis. The PX and PH domains are lipid-binding domains important for the regulation of PLD localization. The loop region, which is absent in PLD2, may play a negative regulatory role for PLD activity. The PIP2-binding domain is important for PLD localization and activity. The sites of interaction of PLD1 with its regulators are also highlighted.
ARF: ADP-ribosylation factor; HKD: Histidine–lysine–aspartic acid; PH: Pleckstrin homology; PKC: Protein kinase C; PLD: Phospholipase D; PtdIns: Phosphoinositide; PX: Phox homology.