Signalling via ADP-ribosylation factor 6 lies downstream of phosphatidylinositide 3-kinase.

ADP-ribosylation factor (ARF) 6 regulates plasma membrane trafficking and cortical actin formation by cycling between inactive GDP and active GTP-bound conformations. Here we show that agonist stimulation of phosphatidylinositide 3-kinase (PI 3-kinase) activates a pathway that leads to ARF6 activation. We also describe experiments that propose a central role in this pathway for the PI 3-kinase-dependent plasma membrane recruitment of the cytohesin-1 family of PtdIns(3,4,5)P(3)-binding ARF-exchange factors.