Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.3.14 (ATP synthase)
 7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rod photoreceptors efficiently carry out phototransduction cascade, an energetically costly process. Our recent data in bovine rod outer segment (OS) demonstrated that ATP for phototransduction is produced by an extramitochondrial oxidative phosphorylation, thanks to the expression of the Electron Transport Chain (ETC) complexes and of F1Fo ATP synthase in disks. Here we have focused on mouse retinas, reporting the activity of ETC complexes I, II, IV assayed directly on unfixed mouse eye sections, as well as immunogold TEM analysis of fixed mouse eye sections to verify the presence of ND4L subunit of ETC complex I and subunit IV of ETC complex IV in rod OS. Data suggest the presence of functional ETC in mouse rod OS, like their bovine counterpart. The protocol here developed for in situ assay of the ETC complexes activity represents a reliable method for the detection of ETC dysfunction in mice models of retinal pathologies. In fact, the ETC is a major source of reactive oxygen intermediates, and oxidative stress, especially when ectopically expressed in the OS. In turn, oxidative stress contributes to many retinal pathologies, such as diabetic retinopathy, age related macular degeneration, photoreceptor death after retinal detachment and some forms of retinitis pigmentosa.
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PMID:Functional expression of electron transport chain complexes in mouse rod outer segments. 2456 9

The retina is the most oxygen consuming tissue of the body. Rod and cone photoreceptors efficiently carry out visual cascades, which are energetically costly processes. Data has recently been published that suggests that the metabolic support to phototransduction in the rod outer segment (OS) may originate directly in the OS, which is able to conduct aerobic metabolism. This oxygen-handling activity of the rod OS, which was never suspected before, appears to be a primary cause of the generation of reactive oxygen species directly inside the OS. Oxidative stress has been hypothesised to contribute to most of the neurodegenerative retinal pathologies, such as diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa and photoreceptor cell death after retinal detachment. Many natural antioxidant compounds are routinely used in experimental or human therapies for preventing or delaying photoreceptor degeneration in those pathologies. Here it is proposed that the ultimate reason for the beneficial actions of antioxidants in preventing or retarding the effect on the retinal degenerative pathologies can be found in their action on reactive oxygen species generated by the ectopic mitochondrial electron transport chain (ETC) coupled to FoF1-ATP synthase in rod OS disks. In fact, if not adequately coupled, the ETC generates reactive oxygen species that, in turn, can act on the polyunsaturated fatty acids which the rod OS is rich in. If correct, the mechanism put forward here would provide a potential for the molecular basis of therapies with antioxidants for retinal degenerative diseases.
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PMID:Beneficial effect of antioxidants in retinopathies: a new hypothesis. 2460 Jun 29