P2X1 and P2X4, but not P2X7, receptors translocate to the immune synapse of T cells. Laser scanning microscopy images of primary human T cells activated with anti-CD3/CD28 antibody–loaded beads (asterisks). Cells were fixed after the indicated stimulation time and stained with anti-P2X1 (A), P2X4 (B), or P2X7 (C) receptor antibodies. While P2X4 receptors rapidly translocate to the immune synapse, P2X1 receptors first aggregate in clusters, and then translocate to the synapse after 15-30 minutes. P2X7 receptors do not redistribute upon TCR/CD28 stimulation and maintain their uniform distribution on the cell surface.