PI3K is activated in Vα14iNKT cells that interact with αGalCer-loaded DCs. Localization of PIP3 to the NKT cell membrane. TCRβ⁺NK1.1⁺HSA^low NKT cells were purified from thymocytes of 8-week-old AktPH-GFP^tg/tg mice (WT for Pten) expressing the PIP3-binding AktPH-GFP bioprobe I (left). These Vα14iNKT cells were incubated with αGalCer-loaded DCs, and PIP3 localization was determined by confocal fluorescence (left) and phase contrast (right) microscopy. (A) Vα14iNKT cells that made contact with αGalCer-loaded DCs showed membrane localization of PIP3 (solid arrow), while PIP3 remained in the cytoplasm of Vα14iNKT cells that did not make contact with DCs (dotted arrows). (B) AktPH-GFP bioprobe localization to the plasma membrane of Vα14iNKT cells was inhibited by wortmannin or by contact with DCs lacking αGalCer.