Hiroki Kato, Kana Nishijima and Naomi Hachiya
We previously demonstrated microtubule (MT)-associated kinesin-driven anterograde and dynein-driven
retrograde trafficking of cellular prion protein in undifferentiated mouse neuro2a (N2a) cells. The NH2-terminal fragment of the fluorescent cellular prion protein residing inside vesicles (hereafter “vesicular GFP-PrPC”) exhibited an anterograde movement towards the direction of the plasma membrane at a speed of 140~ nm/sec, which is comparable to the velocity of KIF4-driven movement, and a retrograde movement inwardly at a speed 1,000 nm/ sec, which is comparable to the velocity of dynein-driven movement. We investigated the behavior of movement of vesicular GFP-PrPC in the neurite by first establishing N2a cells that stably expressed GFP-PrPC and treating these
with NGF for neurite differentiation, followed by real-time imaging. In neurites, the anterograde kinesin-driven velocity of vesicular GFP-PrPC was selectively reduced to ~50 nm/sec, which is comparable to the velocity of KIF5, whereas retrograde dynein-driven velocity remained unchanged. Injection of anti-KIF5 antibody into differentiated N2a cells stably expressing GFP-PrPC inhibited the anterograde movement of vesicular PrP in neurites, which exhibited neuriteassociated bulges that lacked PrPC signals. These data suggest the involvement of a motor switch from KIF4 to KIF5
in PrPC movement in neurites.