Related Experiment Video
Updated: May 17, 2025

Application of High-speed Super-resolution SPEED Microscopy in Live Primary Cilium
Published on: January 16, 2018
Delivery of intraflagellar transport proteins to the ciliary base and assembly into trains
Aniruddha Mitra1, Evangelos Gioukakis1, Wouter Mul1
1Department of Physics and Astronomy and LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
Abstract:
Anterograde intraflagellar transport (IFT) trains, composed of IFT-B, IFT-A, and BBSome subcomplexes, are responsible for transporting ciliary proteins into the cilium. How IFT subcomplexes reach the ciliary base and assemble into IFT trains is poorly understood. Here, we perform quantitative single-molecule imaging in Caenorhabditis elegans chemosensory cilia to uncover how IFT subcomplexes arrive at the base, organize in IFT trains, and enter the cilium. We find that BBSomes reach the base via diffusion where they either associate with assembling IFT trains or with the membrane surrounding the base. In contrast, IFT-B and IFT-A reach the base via directed transport most likely on vesicles that stop at distinct locations near the base. Individual subcomplexes detach from the vesicles into a diffusive pool and associate to assembling trains. Our results show that IFT-B is first incorporated into IFT trains, followed by IFT-A, and finally BBSomes, indicating that the assembly of IFT trains is a highly regulated, step-wise process.
Related Concept Videos
Microtubule Associated Motor Proteins
Microtubules in Cell Motility
Mechanism of Ciliary Motion
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
The Movement of Organelles and Vesicles
Spindle Assembly
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a...
Assembly of Cytoskeletal Filaments

