Myosin II is an actin-binding protein composed of MHC (myosin heavy chain) IIs, RLCs (regulatory light chains) and ELCs (essential light chains). Myosin II expressed in non-muscle tissues plays a central role in cell adhesion, migration and division. The regulation of myosin II activity is known to involve the phosphorylation of RLCs, which increases the Mg2+-ATPase activity of MHC IIs. However, less is known about the details of RLC–MHC II interaction or the loss-of-function phenotypes of non-muscle RLCs in mammalian cells. In the present paper, we investigate three highly conserved non-muscle RLCs of the mouse: MYL (myosin light chain) 12A (referred to as MYL12A), MYL12B and MYL9 (MYL12A/12B/9). Proteomic analysis showed that all three are associated with the MHCs MYH9 (NMHC IIA) and MYH10 (NMHC IIB), as well as the ELC MYL6, in NIH 3T3 fibroblasts. We found that knockdown of MYL12A/12B in NIH 3T3 cells results in striking changes in cell morphology and dynamics. Remarkably, the levels of MYH9, MYH10 and MYL6 were reduced significantly in knockdown fibroblasts. Comprehensive interaction analysis disclosed that MYL12A, MYL12B and MYL9 can all interact with a variety of MHC IIs in diverse cell and tissue types, but do so optimally with non-muscle types of MHC II. Taken together, our study provides direct evidence that normal levels of non-muscle RLCs are essential for maintaining the integrity of myosin II, and indicates that the RLCs are critical for cell structure and dynamics.
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Research Article|
January 27 2011
Myosin regulatory light chains are required to maintain the stability of myosin II and cellular integrity
Inju Park;
Inju Park
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Cecil Han;
Cecil Han
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Sora Jin;
Sora Jin
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Boyeon Lee;
Boyeon Lee
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Heejin Choi;
Heejin Choi
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Jun Tae Kwon;
Jun Tae Kwon
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Dongwook Kim;
Dongwook Kim
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Jihye Kim;
Jihye Kim
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Ekaterina Lifirsu;
Ekaterina Lifirsu
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Woo Jin Park;
Woo Jin Park
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Zee Yong Park;
Zee Yong Park
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Do Han Kim;
Do Han Kim
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
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Chunghee Cho
Chunghee Cho
1
1School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
1To whom correspondence should be addressed (email choch@gist.ac.kr).
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Publisher: Portland Press Ltd
Received:
September 13 2010
Revision Received:
November 23 2010
Accepted:
December 02 2010
Accepted Manuscript online:
December 02 2010
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© The Authors Journal compilation © 2011 Biochemical Society
2011
Biochem J (2011) 434 (1): 171–180.
Article history
Received:
September 13 2010
Revision Received:
November 23 2010
Accepted:
December 02 2010
Accepted Manuscript online:
December 02 2010
Citation
Inju Park, Cecil Han, Sora Jin, Boyeon Lee, Heejin Choi, Jun Tae Kwon, Dongwook Kim, Jihye Kim, Ekaterina Lifirsu, Woo Jin Park, Zee Yong Park, Do Han Kim, Chunghee Cho; Myosin regulatory light chains are required to maintain the stability of myosin II and cellular integrity. Biochem J 15 February 2011; 434 (1): 171–180. doi: https://doi.org/10.1042/BJ20101473
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