Dynamics of the IFT machinery at the ciliary tip

eLife

Ahmet Yildiz¹  Alexander Chien¹  Raqual Bower²  Douglas Tritschler²  Mary E Porter²  Sheng Min Shih³ 

[1] Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States;Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, United States;Physics Department, University of California, Berkeley, Berkeley, United States;

关键词: intraflagellar transport;    kinesin;    dynein;    ciliary length control;    single molecule imaging;    photogate;   

DOI  :  10.7554/eLife.28606

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown