(A) Sequence alignment (top) of the L12 of KIF1A and KIF5C,
highlighting the lysine-rich patch. Cartoon models (bottom) of the structure of
the motor domain of KIF1A alone (left) or superimposed onto KIF5C (right).
(B–D) Bar graphs show percentage neurons (n = 61–110)
with KIF5C(1–560)-L12KIF1A-mCit in the cell body (B) and
proximal dendrites (C). Images (D) show
KIF5C(1–560)-L12KIF1A-mCit localization in hippocampal neurons
transfected with scramble or SEPT9 shRNAs. Red arrowheads point to KIF1A
accumulation at dendritic tips (scramble shRNA), and blue and red arrowheads
point to the base and proximal segments of dendrites, respectively (SEPT9
shRNA). Rescue experiments were performed by co-expressing SEPT9 shRNA with
shRNA-resistant SEPT9-mCherry, SEPT9-Δ(1–147)-mCherry or
SEPT9(1–125)-mCherry (MTBD).
(E) Bar graph shows the mean (±SEM) landing rate of
KIF5C(1–560)-L12KIF1A-mCit on MTs alone (n = 17) or
His-mCherry-SEPT9 (10 nM)-coated MTs (n = 19). (F and G) Histograms shows the
distribution of KIF5C(1–560)-L12KIF1A-mCit velocities (F) and
run lengths (G) on MTs alone (n = 217) or MTs coated with 10 nM HismCherry-SEPT9
(n = 210 events). Bar graph shows mean (±SEM) velocity and run
length.