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Hello, my name is Ryan Mailloux,
and I'm an assistant professor of biochemistry at Memorial University of Newfoundland.
In this lecture, I'll be discussing
controlling mitochondrial reactive oxygen species production for cell signalling.
I will start this lecture with an introduction that focuses on giving a background
on how mitochondria combust carbon to make energy and reactive oxygen species.
This will be followed by a brief discussion on oxygen and its radicals,
and the difference between oxidative eustress, and oxidative distress
and how these two terms properly defined
the dichotomous nature of reactive oxygen species in biology.
This will then be followed by a few slides on
the signalling properties of reactive oxygen species,
focusing specifically on hydrogen peroxide.
I'll then start moving through the core of this lecture,
which is understanding mitochondrial ROS release.
In the first part of this discussion,
I will go through some of the basics of how mitochondria produce reactive oxygen species,
focusing on the 12 different ROS forming sites associated with energy metabolism.
After this, I'll go through controlling mitochondrial reactive oxygen species production
focusing on proton leaks,
supercomplex assemblies, and redox switches.
And then finally, I will discuss the implications of
redox switches in controlling mitochondrial reactive oxygen species signaling.
Mitochondria fulfill various essential functions of metabolism,
which includes meeting cellular energy demands through ATP production.
This is achieved via the combustion of carbon and the liberation of
electrons which are then used to produce ATP by oxidative phosphorylation.
Mitochondria are also the most important source of
cellular reactive oxygen species namely superoxide, and hydrogen peroxide,
the proximal reactive oxygen species generated by mitochondria,
and the most important oxy-radicals formed by biological systems.
Importantly, the formation of superoxide and hydrogen peroxide relies on
the same electron transfer pathways that mitochondria used to make ATP.
And although ROS are damaging at high levels,
it is now appreciated that low grade mitochondrial ROS production
specifically hydrogen peroxide,
is vital for regulating various cellular functions.