TIP30 interacts with Rab5a, ACSL4, and Endo B1. A, immunoblot confirmed the association of Rab5a, ACSL4, and Endo B1 with TIP30. The immunoprecipitates were resolved on SDS-PAGE and analyzed by immunoblotting (IB) with the indicated antibodies. The two polypeptides that reacted with anti-HA antibodies might result from posttranslational modifications on TIP30. Input was 10% (equals 70 μg of protein) of the volume of lysates used in the immunoprecipitation (IP) assays. The EGFR blot serves as a negative control. B, reciprocal co-immunoprecipitation. Whole cell extracts made from cells expressing HA-Rab5a, ACSL4-HA, Endo B1-HA, or empty vector were subjected to co-immunoprecipitation with α-HA-agarose beads. The immunoprecipitates were subjected to immunoblot analysis with the indicated antibodies. Input was 10% of the volume of lysates used in the immunoprecipitation assays. C, bimolecular fluorescence complementation analysis was performed on 293T cells by co-expressing TIP30-VC155 with VN173, VN173-Rab5a, ACSL4-VN173, or Endo B1-VN173. Green indicates fluorescent signal from Venus, a GFP variant. Bottom panels show overlays of differential interference contrast and representative confocal microscope images. Scale bars, 10 μm.