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0:00
I'm Henry Jay Forman,
an emeritus professor at both
the University of
California Merced
and the University of
Southern California.
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This lecture will involve
differentiating between redox
signaling that is part
of normal physiology
and responses to
oxidative stress.
Redox signaling is part
of normal physiology.
As such,
it depends upon regulated
enzymatic activities
rather than
non-enzymatic oxidation.
In contrast,
signaling that occurs in
response to oxidative stress
begins with non enzymatic oxidation
of cellular constituents.
When we model redox signaling
with exogenous oxidants,
we must be aware of this
fundamental difference.
We may be studying chemistry
that can occur in cell culture,
but would be extremely
unlikely in vivo.
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Redox signaling is regulated
by enzymatic activities.
Production of superoxide
and hydrogen peroxide is
by NADPH oxidases and
mitochondrial complexes.
Removal of superoxide
and hydrogen peroxide
is by antioxidant enzymes.
Oxidation of signaling
proteins has specificity
that is largely determined by
the kinetics of thiol oxidation.
Redox signaling is
regulated by agonists.
just as is most signaling.
Generation of oxidants
in metabolism
is regulated by cellular
maintenance requirements.
Basal redox signaling
in cells is regulated
by both agonist-induced
signaling
and metabolic requirements.
