Functional exploration of heterotrimeric kinesin-II in IFT and ciliary length control in Chlamydomonas
Abstract
Heterodimeric motor organization of kinesin-II is essential for its function in anterograde IFT in ciliogenesis. However, the underlying mechanism is not well understood. In addition, the anterograde IFT velocity varies significantly in different organisms, but how this velocity affects ciliary length is not clear. We show that in Chlamydomonas motors are only stable as heterodimers in vivo, which is likely the key factor for the requirement of a heterodimer for IFT. Second, chimeric CrKinesin-II with human kinesin-II motor domains functioned in vitro and in vivo, leading to a ~2.8-fold reduced anterograde IFT velocity and a similar fold reduction in IFT injection rate that supposedly correlates with ciliary assembly activity. However, the ciliary length was only mildly reduced (~15%). Modelling analysis suggests a nonlinear scaling relationship between IFT velocity and ciliary length that can be accounted for by limitation of the motors and/or its ciliary cargoes, e.g. tubulin.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Part of the source data have been provided for Figure 1-4.
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Funding
Ministry of Science and Technology of the People's Republic of China (2017YFA0503500)
- Junmin Pan
Ministry of Science and Technology of the People's Republic of China (2018YFA0902500)
- Junmin Pan
National Natural Science Foundation of China (31991191)
- Junmin Pan
National Natural Science Foundation of China (31671387)
- Junmin Pan
National Natural Science Foundation of China (31972888)
- Junmin Pan
National Natural Science Foundation of China (31922018)
- Xin Liang
Springboard Award from the Academy of Medical Sciences and Global Challenges Research Fund Research Fund (SBF003\1160)
- Kirsty Y Wan
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Li et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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