JIP4 localizes to Phafin2 positive early macropinosomes. Shown is a macropinocytosing RPE1 cell with Phafin2-mTurquoise2 (pseudocolored green) and mNeonGreen-JIP4 (pseudocolored magenta). Note that the nascent macropinosomes entering on the right display a burst of Phafin2 that is not accompanied by JIP4, while the early macropinosomes acquire both Phafin2 and JIP4.