Format

Send to

Choose Destination
EMBO J. 2002 Apr 2;21(7):1616-27.

Mitochondria are morphologically and functionally heterogeneous within cells.

Author information

1
Laboratory of Molecular Signalling, The Babraham Institute, Babraham, Cambridge CB2 4AT, UK. tony.collins@bbsrc.ac.uk

Abstract

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.

PMID:
11927546
PMCID:
PMC125942
DOI:
10.1093/emboj/21.7.1616
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center