Reactive oxygen species: important regulators of the oxygen sensing pathway

Various studies have demonstrated the influence of reactive oxygen species (ROS) in oxygen signaling. However, reports on the effect of ROS on HIF function are controversial as different, even contrasting outcomes on HIF activity have been observed depending on whether ROS are part of a normoxic, hypoxic or growth factor signalling cascade response. Thus, a HIF upregulation upon ROS depletion under normoxia and a HIF downregulation upon ROS increase under hypoxia have been documented. These observations are in line with the concept that declining O2 concentrations trigger the hypoxia response as a result of decr…