Figure 5.

Overexpression of dominant-negative cdk5 inhibits uptake of FM1–43, but not FM2–10. A, Cultures transfected with either WT or DN cdk5 were loaded and unloaded (S1) with either FM2–10 and FM1–43 using 50 mm KCl. Representative images show granule neuron cultures transfected with WT cdk5 and loaded with FM1–43. Merged image shows transfected neuron (green) and FM1–43-loaded nerve terminals (red). Arrows indicate transfected nerve terminals and asterisks indicate untransfected nerve terminals. Note the equal loading of both. B, ΔS1 response in transfected nerve terminals is displayed normalized to the S1 from nontransfected nerve terminals in the same field of view. Open bars, FM2–10; closed bars, FM1–43 (n = 31, WT cdk5 FM2–10; n = 50, DN cdk5 FM2–10; n = 63, WT cdk5 FM1–43; n = 35, DN cdk5 FM1–43; ***p < 0.001, Student's t test). Error bars indicate SEM. For all experiments, n = 3.