Darwin, cientistas descobrem um motor molecular com "engrenagem" de comutação direcional

segunda-feira, janeiro 09, 2017

The mitotic kinesin-14 KlpA contains a context-dependent directionality switch

Andrew R. Popchock, Kuo-Fu Tseng, Pan Wang, P. Andrew Karplus, Xin Xiang & Weihong Qiu

Nature Communications 8, Article number: 13999 (2017)

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KinesinSingle-molecule biophysics

Received: 16 June 2016 Accepted: 17 November 2016 Published online: 04 January 2017

Source/Fonte: Dynamic Science


Kinesin-14s are commonly known as nonprocessive minus end-directed microtubule motors that function mainly for mitotic spindle assembly. Here we show using total internal reflection fluorescence microscopy that KlpA—a kinesin-14 from Aspergillus nidulans—is a context-dependent bidirectional motor. KlpA exhibits plus end-directed processive motility on single microtubules, but reverts to canonical minus end-directed motility when anchored on the surface in microtubule-gliding experiments or interacting with a pair of microtubules in microtubule-sliding experiments. Plus end-directed processive motility of KlpA on single microtubules depends on its N-terminal nonmotor microtubule-binding tail, as KlpA without the tail is nonprocessive and minus end-directed. We suggest that the tail is a de facto directionality switch for KlpA motility: when the tail binds to the same microtubule as the motor domain, KlpA is a plus end-directed processive motor; in contrast, when the tail detaches from the microtubule to which the motor domain binds, KlpA becomes minus end-directed.


We thank Drs C. Mathews (Oregon State University), X. Su (UCSF) and B. Liu (UC Davis) for critical reading of the manuscript, and Mr Chun Liu (Pearl River Fisheries Research Institute, China) for initial plasmid construction. This work was supported in part by the National Science Foundation (MCB-1616462 to W.Q.).

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Author notes

Andrew R. Popchock & Kuo-Fu Tseng

These authors contributed equally to this work


Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA

Andrew R. Popchock, P. Andrew Karplus & Weihong Qiu

Department of Physics, Oregon State University, Corvallis, Oregon 97331, USA

Kuo-Fu Tseng, Pan Wang & Weihong Qiu

School of Physics and Electronics, Henan University, Kaifeng, Henan 475004, China

Pan Wang

Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA

Xin Xiang


W.Q. conceived, designed and supervised the study; A.R.P. and K.-F.T. performed the experiments; K.-F.T. and P.W. contributed all KlpA constructs. All authors participated in discussing and interpreting the results. P.A.K., X.X. and W.Q. wrote the manuscript with input from all other authors.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Weihong Qiu.

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