Exo70 interaction with the exocyst complex and Rab11 during phagosome formation. (A) Cdc42–exocyst association requires Exo70. Control (siGLO) and Exo70 (siExo70)-depleted 293T cells were transfected with constitutively active Cdc42 (Myc-Cdc42V12), Sec8-HA, and Sec3-FLAG. Cells were lysed, and Myc-Cdc42 was precipitated from the cleared lysates using anti-Myc antibody resin. Input and immunoprecipitate (IP) samples were analyzed by SDS-PAGE and Western blotting. Densitometry was used to quantify the amount of Sec8 or Sec3 that precipitated with Myc-Cdc42, which was then normalized to input quantities. (B) Exo70 expression rescues large particle uptake defect in the absence of Rab11 activity. HeLa cells expressing either Exo70 or dominant-negative Rab11 (Rab11S25N) or both were challenged with 4.5-µm beads, and uptake was quantified microscopically. (C) Control (siGLO) or Exo70 (siExo70)-depleted HeLa cells were transfected with an empty plasmid or constitutively active Rab11 (HA-Rab11Q70L) and challenged with 4.5-µm beads. Uptake was quantified microscopically. Error bars represent SEM. **, P < 0.01.