UMMS Affiliation

Department of Radiology, Division of Cell Biology and Imaging; Witman Lab

Publication Date


Document Type



Cell Biology | Cellular and Molecular Physiology | Molecular Biology


Cilia are assembled via intraflagellar transport (IFT). The IFT machinery is composed of motors and multi-subunit particles, termed IFT-A and IFT-B, that carry cargo into the cilium. Knowledge of how the IFT subunits interact with their cargo is of critical importance for understanding how the unique ciliary domain is established. We previously reported a Chlamydomonas mutant, ift46-1, that fails to express the IFT-B protein IFT46, has greatly reduced levels of other IFT-B proteins, and assembles only very short flagella. A spontaneous suppression of ift46-1 restored IFT-B levels and enabled growth of longer flagella, but the flagella lacked outer dynein arms. Here, we show that the suppression is due to insertion of the transposon MRC1 into the ift46-1 allele, causing the expression of a fusion protein including the IFT46 C-terminal 240 amino acids. The IFT46 C-terminus can assemble into and stabilize IFT-B, but does not support transport of outer arm dynein into flagella. ODA16, a cargo adaptor specific for outer arm dynein, also fails to be imported into the flagella in the absence of the IFT46 N-terminus. We conclude that IFT46, ODA16, and the outer dynein arm interact for IFT of the latter.


cilia, flagella, intraflagellar transport, IFT

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© 2017 Hou and Witman. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License ( Publisher PDF posted as allowed by the publisher's author rights policy at

DOI of Published Version



Mol Biol Cell. 2017 Sep 1;28(18):2420-2433. doi: 10.1091/mbc.E17-03-0172. Epub 2017 Jul 12. Link to article on publisher's site

Journal/Book/Conference Title

Molecular biology of the cell

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PubMed ID


Creative Commons License

Creative Commons Attribution-Noncommercial-Share Alike 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.