OsKCH2 is a novel processive minus end-directed kinesin-14 motor

ORAL

Abstract

In animals and fungi, cytoplasmic dynein contains the ability to generate processive minus end-directed motility on single microtubules without having to form multi-motor ensembles and thus plays a dominant role over kinesin-14 motors. However, land plants do not have cytoplasmic dynein, and no plant kinesin-14 motor is known to be able to move processively on single microtubules as a homodimer. Here, we have analyzed the motility of OsKCH2 -- a plant-specific kinesin-14 that contains an N-terminal actin-binding CH domain and a central microtubule-binding motor domain flanked by a pair of putative coiled coils (CC1 and CC2) -- using TIRF microscopy. We found that OsKCH2 transports actin filaments along the microtubules and exhibits processive minus end-directed motility as a homodimer. We have further revealed that only the upstream CC1 forms a coiled coil to enable the formation of OsKCH2 homodimers. In contrast, the downstream CC2 does not form an authentic coiled-coil and instead plays an indispensable role in OsKCH2 processivity by enhancing its binding to the microtubule. Collectively, this study shows that land plants have evolved unconventional kinesin-14 homodimers with inherent minus end-directed processivity that likely compensate for the loss of cytoplasmic dynein.

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Authors

  • Allison Gicking

    Oregon State University

  • Kuo-Fu Tseng

    Idaho Accelerator Center, University of Oregon, Department of Physics, Oregon State Univ, University Of Oregon, Washington State University, Simon Fraser University, University of Southern Queensland, Australia, UC Davis, Oregon State University, Henan University

  • Kuo-Fu Tseng

    Idaho Accelerator Center, University of Oregon, Department of Physics, Oregon State Univ, University Of Oregon, Washington State University, Simon Fraser University, University of Southern Queensland, Australia, UC Davis, Oregon State University, Henan University

  • Kuo-Fu Tseng

    Idaho Accelerator Center, University of Oregon, Department of Physics, Oregon State Univ, University Of Oregon, Washington State University, Simon Fraser University, University of Southern Queensland, Australia, UC Davis, Oregon State University, Henan University

  • Kuo-Fu Tseng

    Idaho Accelerator Center, University of Oregon, Department of Physics, Oregon State Univ, University Of Oregon, Washington State University, Simon Fraser University, University of Southern Queensland, Australia, UC Davis, Oregon State University, Henan University

  • Kuo-Fu Tseng

    Idaho Accelerator Center, University of Oregon, Department of Physics, Oregon State Univ, University Of Oregon, Washington State University, Simon Fraser University, University of Southern Queensland, Australia, UC Davis, Oregon State University, Henan University

  • Kuo-Fu Tseng

    Idaho Accelerator Center, University of Oregon, Department of Physics, Oregon State Univ, University Of Oregon, Washington State University, Simon Fraser University, University of Southern Queensland, Australia, UC Davis, Oregon State University, Henan University

  • Kuo-Fu Tseng

    Idaho Accelerator Center, University of Oregon, Department of Physics, Oregon State Univ, University Of Oregon, Washington State University, Simon Fraser University, University of Southern Queensland, Australia, UC Davis, Oregon State University, Henan University