TRIM9 directly binds the Netrin-1 receptor DCC and colocalizes with DCC in cortical neurons. (A) Bacterially expressed GST-SPRY domain interacts with DCC in embryonic mouse cortical lysate. Protein purity is shown by Coomassie. IB, immunoblot. (B) Sequential overlapping peptides within the cytoplasmic tail of DCC were arrayed on nitrocellulose and probed with GST-SPRY, GST antibodies, and HRP secondary antibodies. The SPRY domain binds two sequences within the cytoplasmic tail of DCC. (C) E15.5 cortical neuron transfected with MycTRIM9 and HA-DCC and cultured for 48 h. Boxes denotes the ROIs shown in the enlarged color-combined image. (D) Neuron transfected with GFP-TRIM9 and mCherry (mCh)-DCC imaged by TIRF. Arrowheads denote colocalization, and time is given in seconds (Video 1).