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Tagging and tracking individual networks within a complex mitochondrial web with photoactivatable GFP

Authors :
Twig, Gilad
Graf, Solomon A.
Wikstrom, Jakob D.
Mohamed, Hibo
Haigh, Sarah E.
Elorza, Alvaro
Deutsch, Motti
Zurgil, Naomi
Reynolds, Nicole
Shirihai, Orian S.
Source :
The American Journal of Physiology. July, 2006, Vol. 291 Issue 1, pC176, 9 p.
Publication Year :
2006

Abstract

Assembly of mitochondria into networks supports fuel metabolism and calcium transport and is involved in the cellular response to apoptotic stimuli. A mitochondrial network is defined as a continuous matrix lumen whose boundaries limit molecular diffusion. Observation of individual networks has proven challenging in live cells that possess dense populations of mitochondria. Investigation into the electrical and morphological properties of mitochondrial networks has therefore not yielded consistent conclusions. In this study we used matrix-targeted, photoactivatable green fluorescent protein to tag single mitochondrial networks. This approach, coupled with real-time monitoring of mitochondrial membrane potential, permitted the examination of matrix lumen continuity and fusion and fission events over time. We found that adjacent and intertwined mitochondrial structures often represent a collection of distinct networks. We additionally found that all areas of a single network are invariably equipotential, suggesting that a heterogeneous pattern of membrane potential within a cell's mitochondria represents differences between discrete networks. Interestingly, fission events frequently occurred without any gross morphological changes and particularly without fragmentation. These events, which are invisible tinder standard confocal microscopy, redefine the mitochondrial network boundaries and result in electrically disconnected daughter units. membrane potential; fusion; fission; heterogeneity; green fluorescent protein; tetramethylrhodamine ethyl ester perchlorate

Details

Language :
English
ISSN :
00029513
Volume :
291
Issue :
1
Database :
Gale General OneFile
Journal :
The American Journal of Physiology
Publication Type :
Academic Journal
Accession number :
edsgcl.148716849