Disrupting KIF5–SNPH interaction abolishes activity-dependent immobilization of axonal mitochondria. (A and B) Kymographs (A) and quantitative analysis (B) showing the motility of axonal mitochondria in neurons expressing GFP-SNPH or GFP-SNPH-ΔKBD. (C) An inhibitory role of KBD in the KIF5C–SNPH interaction. HEK293 cells were transfected with GFP-KIF5C alone or cotransfected with GFP-SNPH or GFP-SNPH + GFP-KBD. The KIF5C–SNPH complex was immunoprecipitated (IP) from the lysates using an anti-KHC antibody followed by immunoblotting (IB) with an anti-GFP antibody. Note that KBD interferes with the interaction of SNPH with KIF5C (top red box) by competitively binding to KIF5C (bottom red box). (D and E) The motility of axonal and dendritic mitochondria in wild-type neurons before and after 100-Hz (2 s) field stimulation. Expressing GFP-KBD abolishes the activity-dependent immobilization of axonal but not dendritic mitochondria (also see Video 8). Data were quantified from numbers of neurons (indicated in parentheses in B and within bars in E) in three independent experiments. Bars, 10 µm. Error bars show SEM. Student’s t test.