Single-Molecule Turnarounds of Intraflagellar Transport at the C. elegans Ciliary Tip

Jona Mijalkovic, Jaap van Krugten, Felix Oswald, Seyda Acar, Erwin J.G. Peterman*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


Cilia are microtubule-based sensing hubs that rely on intraflagellar transport (IFT) for their development, maintenance, and function. Kinesin-2 motors transport IFT trains, consisting of IFT proteins and cargo, from ciliary base to tip. There, trains turn around and are transported back by IFT dynein. The mechanism of tip turnaround has remained elusive. Here, we employ single-molecule fluorescence microscopy of IFT components in the tips of phasmid cilia of living C. elegans. Analysis of the trajectories reveals that while motor proteins and IFT-A particle component CHE-11 mostly turn around immediately, the IFT-B particle component OSM-6 pauses for several seconds. Our data indicate that IFT trains disassemble into at least IFT-A, IFT-B, IFT-dynein, and OSM-3 complexes at the tip, where OSM-6 is temporarily retained or undergoes modification, prior to train reassembly and retrograde transport. The single-molecule approach used here is a valuable tool to study how directional switches occur in microtubule-based transport processes. Using single-molecule fluorescence microscopy, Mijalkovic et al. visualize the dynamics of IFT components at the tips of C. elegans chemosensory cilia. They find that the motors and the IFT-A particle component CHE-11 reverse almost immediately, while the IFT-B component OSM-6 is temporarily retained before reassembly and reversal.

Original languageEnglish
Pages (from-to)1701-1707.e2
Number of pages10
JournalCell Reports
Issue number7
Publication statusPublished - 13 Nov 2018


  • ciliary tip turns
  • dynein
  • IFT
  • intracellular transport
  • kinesin
  • single-molecule biophysics

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