Actin in Mung Bean Mitochondria and Implications for Its Function
Here, a large fraction of plant mitochondrial actin was found to be resistant to protease and high-salt treatments, suggesting it was protected by mitochondrial membranes. A portion of this actin became sensitive to protease or high-salt treatment after removal of the mitochondrial outer membrane, i...
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Published in | The Plant cell Vol. 23; no. 10; pp. 3727 - 3744 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Society of Plant Biologists
01.10.2011
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Subjects | |
Online Access | Get full text |
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Summary: | Here, a large fraction of plant mitochondrial actin was found to be resistant to protease and high-salt treatments, suggesting it was protected by mitochondrial membranes. A portion of this actin became sensitive to protease or high-salt treatment after removal of the mitochondrial outer membrane, indicating that some actin is located inside the mitochondrial outer membrane. The import of an actin-green fluorescent protein (GFP) fusion protein into the mitochondria in a transgenic plant, actimGFP, was visualized in living cells and demonstrated by flow cytometry and immunoblot analyses. Polymerized actin was found in mitochondria ofactimGFP plants and in mung bean (Vigna radiata). Notably, actin associated with mitochondria purified from early-developing cotyledons during seed germination was sensitive to high-salt and protease treatments. With cotyledon aging, mitochondrial actin became more resistant to both treatments. The progressive import of actin into cotyledon mitochondria appeared to occur in concert with the conversion of quiescent mitochondria into active forms during seed germination. The binding of actin to mitochondrial DNA (mtDNA) was demonstrated by liquid chromatography-tandem mass spectrometry analysis. Porin and ADP/ATP carrier proteins were also found in mtDNA-protein complexes. Treatment with an actin depolymerization reagent reduced the mitochondrial membrane potential and triggered the release of cytochrome C. The potential function of mitochondrial actin and a possible actin import pathway are discussed. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 The author responsible for the distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantcell.org) is: Hwa Dai (bodaihwa@gate.sinica.edu.tw). Online version contains Web-only data. Current address: Department of Biotechnology, School of Biotechnology and Health Sciences, Karunya University, Coimbatore-641114, Tamil Nadu, India. www.plantcell.org/cgi/doi/10.1105/tpc.111.087403 Open Access articles can be viewed online without a subscription. |
ISSN: | 1040-4651 1532-298X |
DOI: | 10.1105/tpc.111.087403 |