In the Drosophila melanogaster compound eye, myosin-5 (DmM5) plays two distinct roles in response to light stimulation: transport of pigment granules to the rhabdomere base to decrease light exposure and transport of rhodopsin-bearing vesicles to the rhabdomere base to compensate for the rhodopsin loss during light exposure. However, little is known of how the motor function of DmM5 is regulated at the molecular level. In the present study, we overexpressed DmM5 in Sf9 insect cells and investigated its regulation using purified proteins. We found that the actin-activated ATPase activity of DmM5 is significantly lower than that of the truncated DmM5 having the C-terminal globular tail domain (GTD) deleted, indicating that the GTD is the inhibitory domain. The actin-activated ATPase activity of DmM5 is significantly activated by micromolar levels of calcium. DmM5 associates with pigment granules and rhodopsin-bearing vesicles through cargo-binding proteins Lightoid (Ltd) and dRab11 respectively. We found that GTP-bound dRab11, but not Ltd, significantly activates DmM5 actin-activated ATPase activity. Moreover, we identified Gln1689 in the GTD as the critical residue for the interaction with dRab11 and activation of DmM5 motor function by dRab11. Based on those results, we propose that DmM5-dependent transport of pigment granules is directly activated by light-induced calcium influx and the DmM5-dependent transport of rhodopsin-bearing vesicle is activated by active GTP-bound dRab11, whose formation is stimulated by light-induced calcium influx.
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Research Article|
June 19 2015
The motor function of Drosophila melanogaster myosin-5 is activated by calcium and cargo-binding protein dRab11
Huan-Hong Ji;
Huan-Hong Ji
*Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
†University of Chinese Academy of Sciences, Beijing 100049, China
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Hai-Man Zhang;
Hai-Man Zhang
*Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
†University of Chinese Academy of Sciences, Beijing 100049, China
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Mei Shen;
Mei Shen
*Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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Lin-Lin Yao;
Lin-Lin Yao
*Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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Xiang-dong Li
Xiang-dong Li
1
*Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
1To whom correspondence should be addressed (email lixd@ioz.ac.cn).
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Publisher: Portland Press Ltd
Received:
November 21 2014
Revision Received:
May 04 2015
Accepted:
May 05 2015
Accepted Manuscript online:
May 05 2015
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 2015 Authors; published by Portland Press Limited
2015
Biochem J (2015) 469 (1): 135–144.
Article history
Received:
November 21 2014
Revision Received:
May 04 2015
Accepted:
May 05 2015
Accepted Manuscript online:
May 05 2015
Citation
Huan-Hong Ji, Hai-Man Zhang, Mei Shen, Lin-Lin Yao, Xiang-dong Li; The motor function of Drosophila melanogaster myosin-5 is activated by calcium and cargo-binding protein dRab11. Biochem J 1 July 2015; 469 (1): 135–144. doi: https://doi.org/10.1042/BJ20141330
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