[Frontiers in Bioscience 14, 4189-4198, January 1, 2009]

News and views on mitochondrial water transport

Patrizia Gena1,2, Elena Fanelli1, Catherine Brenner3, Maria Svelto1, Giuseppe Calamita1

1Dipartimento di Fisiologia Generale ed Ambientale, Università degli Studi di Bari, Bari, Italy, 2Department of Physiology, Johns Hopkins University, Baltimore (MD), USA, 3Université de Versailles-St Quentin, PRES UniverSud Paris, CNRS UMR 8159, Versailles, France

TABLE OF CONTENTS

1. Abstract dt>2. Water transport in mitochondrial volume homeostasis
3. Structural, biophysical and technical constraints in the assessment of mitochondrial water permeability
4. The high water permeability and presence of aquaporins in mitochondria is the object of much debate
5. Classical and non-classical permeability transition pores and mitochondrial water permeability: is there any relationship?
6. Working model of the movement of water across mitochondrial membranes
7. Concluding remarks and future perspectives
8. Acknowledgments
9. References

1. ABSTRACT

The osmotic movement of water into and out of the mitochondrial matrix underlies the extraordinary plasticity that characterizes mitochondria, a feature of pivotal importance to cell bioenergetics and signaling, and of critical relevance to life-and-death cell decision. However, the biophysics and identity of mitochondrial water transport had remained mostly unexplored, until recent works suggesting high water permeability and the presence of multiple facilitated pathways of water diffusion in liver mitochondria. Here, we attempt to summarize our current view of the mechanisms of mitochondrial water transport and possible relevance of the channel-mediated pathways created by mitochondrial permeability transition, aquaporins and protein/lipid specializations. Assessing the molecular bases and dynamics of mitochondrial water permeability will help to answer the much-debated question over the role of mitochondria