TY - JOUR TI - Dynamics of the IFT machinery at the ciliary tip AU - Chien, Alexander AU - Shih, Sheng Min AU - Bower, Raqual AU - Tritschler, Douglas AU - Porter, Mary E AU - Yildiz, Ahmet A2 - Akhmanova, Anna VL - 6 PY - 2017 DA - 2017/09/20 SP - e28606 C1 - eLife 2017;6:e28606 DO - 10.7554/eLife.28606 UR - https://doi.org/10.7554/eLife.28606 AB - Intraflagellar transport (IFT) is essential for the elongation and maintenance of eukaryotic cilia and flagella. Due to the traffic jam of multiple trains at the ciliary tip, how IFT trains are remodeled in these turnaround zones cannot be determined by conventional imaging. Using PhotoGate, we visualized the full range of movement of single IFT trains and motors in Chlamydomonas flagella. Anterograde trains split apart and IFT complexes mix with each other at the tip to assemble retrograde trains. Dynein-1b is carried to the tip by kinesin-II as inactive cargo on anterograde trains. Unlike dynein-1b, kinesin-II detaches from IFT trains at the tip and diffuses in flagella. As the flagellum grows longer, diffusion delays return of kinesin-II to the basal body, depleting kinesin-II available for anterograde transport. Our results suggest that dissociation of kinesin-II from IFT trains serves as a negative feedback mechanism that facilitates flagellar length control in Chlamydomonas. KW - intraflagellar transport KW - kinesin KW - dynein KW - ciliary length control KW - single molecule imaging KW - photogate JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -