CHCHD4 Regulates Intracellular Oxygenation and Perinuclear Distribution of Mitochondria
Frontiers in Oncology
MetadataShow full item record
Ashcroft, M., Thomas, L., Staples, O., & Turmaine, M. (2017). CHCHD4 Regulates Intracellular Oxygenation and Perinuclear Distribution of Mitochondria. Frontiers in Oncology, 7 (71)https://doi.org/10.3389/fonc.2017.00071
Hypoxia is a characteristic of the tumor microenvironment and is known to contribute to tumor progression and treatment resistance. Hypoxia-inducible factor (HIF) dimeric transcription factors control the cellular response to reduced oxygenation by regulating the expression of genes involved in metabolic adaptation, cell motility, and survival. Alterations in mitochondrial metabolism are not only a downstream consequence of HIF-signaling but mitochondria reciprocally regulate HIF signaling through multiple means, including oxygen consumption, metabolic intermediates, and reactive oxygen species generation. CHCHD4 is a redox-sensitive mitochondrial protein, which we previously identified and showed to be a novel regulator of HIF and hypoxia responses in tumors. Elevated expression of CHCHD4 in human tumors correlates with the hypoxia gene signature, disease progression, and poor patient survival. Here, we show that either long-term (72 h) exposure to hypoxia (1% O2) or elevated expression of CHCHD4 in tumor cells in normoxia leads to perinuclear accumulation of mitochondria, which is dependent on the expression of HIF-1α. Furthermore, we show that CHCHD4 is required for perinuclear localization of mitochondria and HIF activation in response to long-term hypoxia. Mutation of the functionally important highly conserved cysteines within the Cys-Pro-Cys motif of CHCHD4 or inhibition of complex IV activity (by sodium azide) redistributes mitochondria from the perinuclear region toward the periphery of the cell and blocks HIF activation. Finally, we show that CHCHD4-mediated perinuclear localization of mitochondria is associated with increased intracellular hypoxia within the perinuclear region and constitutive basal HIF activation in normoxia. Our study demonstrates that the intracellular distribution of the mitochondrial network is an important feature of the cellular response to hypoxia, contributing to hypoxic signaling via HIF activation and regulated by way of the cross talk between CHCHD4 and HIF-1α.
hypoxia, hypoxia-inducible factor-1α, mitochondria, mitochondrial localization, perinuclear, coiled-coil helix coiled-coil helix domain containing 4
The laboratory is funded in part by Cancer Research UK (CR-UK), the Medical Research Council (MRC). LT was funded by MRC grants MR/K002201/1 and MR/K002201/2 and OS was funded by CR-UK grant C7358/A11223.
Cancer Research UK (19442)
External DOI: https://doi.org/10.3389/fonc.2017.00071
This record's URL: https://www.repository.cam.ac.uk/handle/1810/264488