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Regulating iron seems to be essential
Regulating iron seems to be essential
: Arch Biochem Biophys. 2007 Feb 2; [Epub ahead of print]Autophagy,
ageing and apoptosis: The role of oxidative stress and lysosomal iron.
Kurz T, Terman A, Brunk UT.
Division of Pharmacology, Faculty of Health Sciences, Linkoping
University, Linkoping, Sweden.
As an outcome of normal autophagic degradation of ferruginous
materials, such as ferritin and mitochondrial metalloproteins, the
lysosomal compartment is rich in labile iron and, therefore, sensitive
to the mild oxidative stress that cells naturally experience because
of their constant production of hydrogen peroxide. Diffusion of
hydrogen peroxide into the lysosomes results in Fenton-type reactions
with the formation of hydroxyl radicals and ensuing peroxidation of
lysosomal contents with formation of lipofuscin that amasses in long-
lived postmitotic cells. Lipofuscin is a non-degradable polymeric
substance that forms at a rate that is inversely related to the
average lifespan across species and is built up of aldehyde-linked
protein residues. The normal accumulation of lipofuscin in lysosomes
seems to reduce autophagic capacity of senescent postmitotic cells-
probably because lipofuscin-loaded lysosomes continue to receive newly
formed lysosomal enzymes, which results in lack of such enzymes for
autophagy. The result is an insufficient and declining rate of
autophagic turnover of worn-out and damaged cellular components that
consequently accumulate in a way that upsets normal metabolism. In the
event of a more substantial oxidative stress, enhanced formation of
hydroxyl radicals within lysosomes jeopardizes the membrane stability
of particularly iron-rich lysosomes, specifically of
autophagolysosomes that have recently participated in the degradation
of iron-rich materials. For some time, the rupture of a limited number
of lysosomes has been recognized as an early upstream event in many
cases of apoptosis, particularly oxidative stress-induced apoptosis,
while necrosis results from a major lysosomal break. Consequently, the
regulation of the lysosomal content of redox-active iron seems to be
essential for the survival of cells both in the short- and the long-
term.
PMID: 17306211 [PubMed - as supplied by publisher]
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Tom
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DEAD PEOPLE WALKING
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: Arch Biochem Biophys. 2007 Feb 2; [Epub ahead of print]Autophagy,
ageing and apoptosis: The role of oxidative stress and lysosomal iron.
Kurz T, Terman A, Brunk UT.
Division of Pharmacology, Faculty of Health Sciences, Linkoping
University, Linkoping, Sweden.
As an outcome of normal autophagic degradation of ferruginous
materials, such as ferritin and mitochondrial metalloproteins, the
lysosomal compartment is rich in labile iron and, therefore, sensitive
to the mild oxidative stress that cells naturally experience because
of their constant production of hydrogen peroxide. Diffusion of
hydrogen peroxide into the lysosomes results in Fenton-type reactions
with the formation of hydroxyl radicals and ensuing peroxidation of
lysosomal contents with formation of lipofuscin that amasses in long-
lived postmitotic cells. Lipofuscin is a non-degradable polymeric
substance that forms at a rate that is inversely related to the
average lifespan across species and is built up of aldehyde-linked
protein residues. The normal accumulation of lipofuscin in lysosomes
seems to reduce autophagic capacity of senescent postmitotic cells-
probably because lipofuscin-loaded lysosomes continue to receive newly
formed lysosomal enzymes, which results in lack of such enzymes for
autophagy. The result is an insufficient and declining rate of
autophagic turnover of worn-out and damaged cellular components that
consequently accumulate in a way that upsets normal metabolism. In the
event of a more substantial oxidative stress, enhanced formation of
hydroxyl radicals within lysosomes jeopardizes the membrane stability
of particularly iron-rich lysosomes, specifically of
autophagolysosomes that have recently participated in the degradation
of iron-rich materials. For some time, the rupture of a limited number
of lysosomes has been recognized as an early upstream event in many
cases of apoptosis, particularly oxidative stress-induced apoptosis,
while necrosis results from a major lysosomal break. Consequently, the
regulation of the lysosomal content of redox-active iron seems to be
essential for the survival of cells both in the short- and the long-
term.
PMID: 17306211 [PubMed - as supplied by publisher]
Who loves ya.
Tom
Jesus Was A Vegetarian!
* jesuswasavegetarian.7h . com
Man Is A Herbivore!
* tinyurl . com /a3cc3
DEAD PEOPLE WALKING
* tinyurl . com /zk9fk
