Loading…
Mitochondrial cytochrome oxidase produces nitric oxide under hypoxic conditions: Implications for oxygen sensing and hypoxic signaling in eukaryotes
Eukaryotic cells respond to low-oxygen concentrations by upregulating hypoxic nuclear genes (hypoxic signaling). Although it has been shown previously that the mitochondrial respiratory chain is required for hypoxic signaling, its underlying role in this process has been unclear. Here, we find that...
Saved in:
Published in: | Cell metabolism 2006-04, Vol.3 (4), p.277-287 |
---|---|
Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | Eukaryotic cells respond to low-oxygen concentrations by upregulating hypoxic nuclear genes (hypoxic signaling). Although it has been shown previously that the mitochondrial respiratory chain is required for hypoxic signaling, its underlying role in this process has been unclear. Here, we find that yeast and rat liver mitochondria produce nitric oxide (NO) at dissolved oxygen concentrations below 20 μM. This NO production is nitrite (NO
2
−) dependent, requires an electron donor, and is carried out by cytochrome
c oxidase in a pH-dependent fashion. Mitochondrial NO production in yeast is influenced by the YHb flavohemoglobin NO oxidoreductase, stimulates expression of the hypoxic nuclear gene
CYC7, and is accompanied by an increase in protein tyrosine nitration. These findings demonstrate an alternative role for the mitochondrial respiratory chain under hypoxic or anoxic conditions and suggest that mitochondrially produced NO is involved in hypoxic signaling, possibly via a pathway that involves protein tyrosine nitration. |
---|---|
ISSN: | 1550-4131 1932-7420 |
DOI: | 10.1016/j.cmet.2006.02.011 |