Figure 2.
Kymograms visualizing the time-dependent response of the IFT machinery to external manipulation
(A) Compressing the cilium with a soft wedge creates a small band where IFT cannot pass (horizontal white lines in the kymogram, created by the accumulation of stopped fluorescent trains). After the blockage is applied, trains build up and shortly after start moving in retrograde direction. The approximate location of the ciliary tips is outlined for clarity in purple. See also Video S1.
(B) Detail view of the region between the cell body and the block (white square) in (A). About 2.5 s after IFT is locally blocked, retrograde trains can be seen moving towards the cell body at normal speed (white arrows).
(C) Kymogram of wedge blocking experiment in severely calcium-depleted cilia (see also Figure S1 and Videos S2 and S3). Transport and conversion show no discernable difference to (A) where calcium is available.
(D) In lithium-treated cells, the motors are chemically inhibited and pile up at variable distances from the ciliary tip. Gliding of the cell dislodges the stuck trains, which immediately move in retrograde direction at high speed (≈10 μm s−1) (insert). Anterograde trains are colored in green, while retrograde trains are colored in magenta.