IFT trains in different stages of assembly queue at the ciliary base for consecutive release into the cilium
Jenna L Wingfield,
Ilaria Mengoni,
Heather Bomberger,
Yu-Yang Jiang,
Jonathon D Walsh,
Jason M Brown,
Tyler Picariello,
Deborah A Cochran,
Bing Zhu,
Junmin Pan,
Jonathan Eggenschwiler,
Jacek Gaertig,
George B Witman,
Peter Kner,
Karl Lechtreck
Affiliations
Jenna L Wingfield
Department of Cellular Biology, University of Georgia, Athens, United States
Ilaria Mengoni
Department of Cellular Biology, University of Georgia, Athens, United States
Heather Bomberger
Department of Cellular Biology, University of Georgia, Athens, United States; College of Engineering, University of Georgia, Athens, United States
Yu-Yang Jiang
Department of Cellular Biology, University of Georgia, Athens, United States
Jonathon D Walsh
Department of Genetics, University of Georgia, Athens, United States
Jason M Brown
Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, United States; Department of Biology, Salem State University, Salem, United States
Tyler Picariello
Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, United States
Deborah A Cochran
Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, United States
Bing Zhu
MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
Junmin Pan
MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
Jonathan Eggenschwiler
Department of Genetics, University of Georgia, Athens, United States
Jacek Gaertig
Department of Cellular Biology, University of Georgia, Athens, United States
George B Witman
Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, United States
Peter Kner
College of Engineering, University of Georgia, Athens, United States
Intraflagellar transport (IFT) trains, multimegadalton assemblies of IFT proteins and motors, traffic proteins in cilia. To study how trains assemble, we employed fluorescence protein-tagged IFT proteins in Chlamydomonas reinhardtii. IFT-A and motor proteins are recruited from the cell body to the basal body pool, assembled into trains, move through the cilium, and disperse back into the cell body. In contrast to this ‘open’ system, IFT-B proteins from retrograde trains reenter the pool and a portion is reused directly in anterograde trains indicating a ‘semi-open’ system. Similar IFT systems were also observed in Tetrahymena thermophila and IMCD3 cells. FRAP analysis indicated that IFT proteins and motors of a given train are sequentially recruited to the basal bodies. IFT dynein and tubulin cargoes are loaded briefly before the trains depart. We conclude that the pool contains IFT trains in multiple stages of assembly queuing for successive release into the cilium upon completion.
