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Kinesin-4 Functions in Vesicular Transport on Cortical Microtubules and Regulates Cell Wall Mechanics during Cell Elongation in Plants.



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Kong, Zhaosheng 
Ioki, Motohide 
Braybrook, Siobhan 
Li, Shundai 
Ye, Zheng-Hua 


In plants, anisotropic cell expansion depends on cortical microtubules that serve as tracks along which macromolecules and vesicles are transported by the motor kinesins of unknown identities. We used cotton (Gossypium hirsutum) fibers that underwent robust elongation to discover kinesins that are involved in cell elongation and found Gh KINESIN-4A expressed abundantly. The motor was detected by immunofluorescence on vesicle-like structures that were associated with cortical microtubules. In Arabidopsis thaliana, the orthologous motor At KINESIN-4A/FRA1, previously implicated in cellulose deposition during secondary growth in fiber cells, was examined by live-cell imaging in cells expressing the fluorescently tagged functional protein. The motor decorated vesicle-like particles that exhibit a linear movement along cortical microtubules with an average velocity of 0.89 μm/min, which was significantly different from those linked to cellulose biosynthesis. We also discovered that At KINESIN-4A/FRA1 and the related At KINESIN-4C play redundant roles in cell wall mechanics, cell elongation, and the axial growth of various vegetative and reproductive organs, as the loss of At KINESIN-4C greatly enhanced the defects caused by a null mutation at the KINESIN-4A/FRA1 locus. The double mutant displayed a lack of cell wall softening at normal stages of rapid cell elongation. Furthermore, enhanced deposition of arabinose-containing carbohydrate was detected in the kinesin-4 mutants. Our findings established a connection between the Kinesin-4-based transport of cargoes containing non-cellulosic components along cortical microtubules and cell wall mechanics and cell elongation in flowering plants.


This is the accepted manuscript. The final version is available at


Arabidopsis, cotton, cytoskeleton, cytoskeleton–cell wall interactions, leaf/vegetative development, Animals, Arabidopsis, Arabidopsis Proteins, Biological Transport, Cell Wall, Elasticity, Gossypium, Kinesins, Mice, Microtubules, Mutation, Protein Transport, Seeds

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Mol Plant

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Elsevier BV
Biotechnology and Biological Sciences Research Council (BB/L002884/1)
US Department of Energy (via Pennsylvania State University) (DE-SC0001090)
This report is based on work supported by the National Science Foundation under grant MCB-1243959 (BL and YRJL), Physical Biosciences Program of the Office of Basic Energy Sciences of the U.S. Department of Energy under the contracts DE-FG02-04ER15554 (BL) and DEFG02- 03ER15415 (Z-HY). SL is supported by the Center for LignoCellulose Structure and Formation, an Energy Frontier Research Center funded by the U.S. Department of Energy under the award DE-SC0001090 and SAB is supported by a Gatsby Foundation Fellowship.