Mitochondria are morphologically and functionally heterogeneous within cells

By Tony J. Collins, M. Berridge, P. Lipp, M. Bootman. EMBO Journal, 2002

615 citations recorded by the source corpus.

We investigated whether mitochondria represent morphologically continuous and functionally homogenous entities within single intact cells. Physical continuity of mitochondria was determined by three‐dimensional reconstruction of fluorescence from mitochondrially targeted DsRed1 or calcein. The mitochondria of HeLa, PAEC, COS‐7, HUVEC, hepatocytes, cortical astrocytes and neuronal cells all displayed heterogeneous distributions and were of varying sizes. There was a denser aggregation of mitochondria in perinuclear positions than in the cell periphery, where individual isolated mitochondria could be seen clearly. Using fluorescence‐recovery after photobleaching, we observed that DsRed1 and calcein were highly mobile within the matrix of individual mitochondria, and that mitochondria within a cell were not lumenally continuous. Mitochondria were not electrically coupled, since only individual mitochondria were observed to depolarize following irradiation of TMRE‐loaded cells. Functional heterogeneity of mitochondria in single cells was observed with respect to membrane potential, sequestration of hormonally evoked cytosolic calcium signals and timing of permeability transition pore opening in response to tert‐butyl hydroperoxide. Our data indicate that mitochondria within individual cells are morphologically heterogeneous and unconnected, allowing them to have distinct functional properties.

Subfields: Molecular Biology

View Paper: https://www.semanticscholar.org/paper/ed96605ff7e5461156164d8226a54aa45e9ca9b8

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In Molecular Biology

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Citations in the corpus

• Mitochondrial dynamics in mammalian health and disease. (2009, background): “Importantly, the factors that control and determine these differences in mitochondrial dynamics or architecture among distinct cells lines (63), cell types, or tissues have not been determined.”
• Structural and functional features and significance of the physical linkage between ER and mitochondria (2006, background): “Notably, mitochondria exhibit structural and functional diversity (Collins et al., 2002), and subsets of mitochondria may interact locally with other organelles (Hoth et al.”
• Dynamics of mitochondrial morphology in healthy cells and during apoptosis (2003, background): “In addition to their appearance as network-like, functionally united organelles, mitochondria also can be morphologically and functionally independent within cells.(12,13) It has been”
• Mitochondria and neuronal activity. (2007, background): “Additionally, ultrastructural and confocal laser-scanning microscope studies suggest that the distribution of the mitochondrial population in neurons and glial cells is largely heterogeneous and dynamically changing (44, 49, 149, 177).”
• Mitochondrial membrane potential (2017, background): “[105]) and in the tissue [87], or by the redox status, measured by fluorescence of flavin nucleotides [103,106].”
• Mitochondria in health and disease: perspectives on a new mitochondrial biology. (2004, background): “Other studies fail to support this concept (Nitschke et al., 1997; Collins et al., 2002; Collins and Bootman, 2003).”
• Mitochondrial fusion and fission in cell life and death (2010, background): “By contrast, in quiescent cells mitochondria are frequently present as numerous morphologically and functionally distinct small spheres or short rod”
• Mitochondrial fusion in human cells is efficient, requires the inner membrane potential, and is mediated by mitofusins. (2002, background): “Separate mitochondria will thus remain heterogeneous and behave as independent entities during shorter time periods, as reported (Park et al., 2001; Collins et al., 2002).”
• Mitofusins Mfn1 and Mfn2 coordinately regulate mitochondrial fusion and are essential for embryonic development (2003, background): “However, at any given time point individual mitochondria are functionally distinct entities (Collins et al., 2002).”