We know that ROS stabilizes HIF-1a during hypoxic condition. But the point is how much ROS (conc.) is required for HIF-1a stabilization? Please refer me the related articles. Many thanks!
Dear Amna,
It is possible that ROS concentration could be different depending on cell type; for example in human prostate cancer cells it is necessary 0.5 mM H2O2 or 100 uM menadione (please see Jung et al, 2008).
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http://carcin.oxfordjournals.org/content/29/4/713.full.pdf
The problem is that there are both results which indicate an effect of ROS on HIF and others that don't. #Although some studies suggest
that oxidative conditions, and increased production of reactive
oxygen species decrease the activity of HIF-1a protein
(Haddad et al., 2000; Yang et al., 2003), others have failed to
observe an effect of reactive oxygen species (or cellular redox
state) on HIF-1a function (Lando et al., 2000; Srinivas et al.,
2001)." Thus, without a more accurate explanation, I would guess that there are at least cell type differences. The attached article may be of interest to you.