To survive, Caenorhabditis elegans depends on sensing soluble chemicals with transmembrane proteins (TPs) in the cilia of its chemosensory neurons. Cilia rely on intraflagellar transport (IFT) to facilitate the distribution of cargo, such as TPs, along the ciliary axoneme. Here, we use fluorescence imaging of living worms and perform single-molecule tracking experiments to elucidate the dynamics underlying the ciliary distribution of the sensory TP OCR-2. Quantitative analysis reveals that the ciliary distribution of OCR-2 depends on an intricate interplay between transport modes that depends on the specific location in the cilium: in dendrite and transition zone, directed transport is predominant. Along the cilium motion is mostly due to normal diffusion together with a small fraction of directed transport, while at the ciliary tip subdiffusion dominates. These insights in the role of IFT and diffusion in ciliary dynamics contribute to a deeper understanding of ciliary signal transduction and chemosensing.
Bibliographical noteFunding Information:
We thank J. Mijalkovic for helpful discussion and support, and Laurent Cognet and Antoine Godin (University of Bordeaux) for help and discussions regarding the analysis of single-molecule trajectories. We acknowledge financial support from the Netherlands Organisation for Scientific Research (NWO) via a Foundation for Fundamental Research on Matter (FOM) program grant (“The Signal is the Noise”) and from the European Research Council under the European Union’s Horizon 2020 research and innovation program (Grant agreement no. 788363; “HITSCIL”).
© 2022, The Author(s).