Nhe1 is required for directional sensing in vegetative Dictyostelium cell migration.

Na+/H+ exchanger 1 (Nhe1) is a crucial regulator of pH homeostasis and the present study demonstrates that Nhe1 is required for directional sensing in vegetative Dictyostelium cell migration. nhe1 null cells exhibited severe defects in directional sensing and migration in response to folate gradients and applied electric fields.Specifically, nhe1 null cells failed to exhibit proper translocation of phosphatidylinositol (3,4,5)-trisphosphate (PIP3) to the cell cortex and showed abnormal intracellular calcium signaling upon folate stimulation. Additionally, cells lacking Nhe1 exhibited a reduced capacity to engulf bacteria and latex beads. In contrast, nhe1 null cells in the developed stage displayed a defect in cAMP-directed chemotaxis, but normal translocation kinetics of PIP3 to the cell cortex upon cAMP stimulation.