Mitochondria and ATP Synthesis - YouTube

What are the cellular mechanism(s) underlying the observed inability of embryonic neurons to produce ATP by mitochondrial OxPhos? One obvious reason for this inability could be the malfunctioning of F1Fo-ATPase. The activity of this ATP synthase is known to be regulated by polypeptides such as the inhibitory factor IF1 (Pullman and Monroy, ; Klein et al., ) or the calcium-binding ATPase inhibitor protein CaBI (Yamada and Huzel, ). A plausible function for IF1 is to prevent conversion of ATP synthase into ATPase at low ΔΨm, thus preventing premature depletion of [ATP]c under conditions requiring active ATP consumption (Campanella et al., , ). A somewhat similar role for CaBI may be to stimulate, in a Ca2+-dependent manner, ATP synthesis and inhibit ATP hydrolysis by F1Fo-ATPase (Yamada and Huzel, ). While we were not able to find any published evidence for developmental regulation of either IF1 or CaBI expression, our present data seem to indicate that in its reverse (ATP-hydrolysing) mode, the F1Fo-ATPase was functional in our embryonic hippocampal neurons (see Table ). It seems plausible to suggest that F1Fo-ATPase may have been capable of ATP synthesis too, but was not functioning in this particular mode due to other reasons. It has been suggested, however, that transition from ATP-synthesizing mode to the ATP-hydrolysing one is not a mere reversal of the direction in which the Fo and central stalk rotary motor rotate against the F1 stator, but may involve distinct conformational changes (Vinogradov, ; Gao et al., ). Thus, we cannot rule out a possibility that F1Fo-ATPase was, indeed, dysfunctional specifically in its ATP-synthesizing mode. Further experiments would be required to test this hypothesis.

T1 - ATP synthesis is coupled to rat liver mitochondrial RNA synthesis

Perry AJ, Rimmer KA, Mertens HDT et al. (2008) Structure, topology and function of the translocase of the outer membrane of mitochondria. Plant Physiology and Biochemistry 46: 265–274.

ATP Synthesis in Mitochondria - A Level Biology - …

Mitochondria participate in the biosynthesis of a range of coenzymes and vitamins.

V-ATPases (for ‘’)are found in the eukaryotic endomembrane system (vacuoles, Golgi apparatus,endosomes, lysosomes, clathrin-coated vesicles {transport external substancesinside the cell}, and plant tonolplasts), and in the plasma membrane ofprokaryotes and certain specialised eukaryotic cells. V-ATPases hydrolyse ATPto drive a proton pump, but cannot work in reverse to synthesize ATP.V-ATPases are involved in a variety of vitalintra- and inter-cellular processes such as receptor mediated endocytosis,protein trafficking, active transport of metabolites, homeostasis andneurotransmitter release

Energy Conversion: Mitochondria and ATP Production 2

The commonly accepted belief is that neuronal ATP is produced primarily by mitochondrial OxPhos and that glycolytic ATP synthesis plays a minor role in neurons (see for recent reviews, Cheng et al., ; Chinopoulos and Adam-Vizi, ; Shetty et al., and references therein). It was, therefore, a most surprising and unexpected finding of this work that ~84% (96/114) cultured embryonic hippocampal neurons, in contrast to their postnatal counterparts and in disagreement with the conventional view, failed to use their mitochondria to produce and maintain ATP.

ATP synthesis is coupled to rat liver mitochondrial RNA synthesis

It is known that TCA supplies substrates for the respiratory chain in form of NADH for complex I and succinate for complex II. Mitochondrial NAD(P)H level changes can be estimated from intracellular autofluorescence and has long been used as an important and convenient readout of cellular metabolic status (Chance and Hollunger, ; Duchen et al., ; Pellerin and Magistretti, ; Ying, ). We therefore monitored endogenous NAD(P)H fluorescence as an averaged signal from non-transfected cells located in the same visual field as the cells expressing ATP1.03, and compared the time course of simultaneously recorded changes in NAD(P)H and ΔΨm induced by Gluc deprivation and pharmacological manipulations (Figure ; see also Appendix Figure ).

3 ATP synthesis is coupled to rat liver mitochondrial RNA ..

Sweetlove LJ, Fait A, Nunes‐Nesi A, Williams T and Fernie AR (2007) The mitochondrion: an integration point of cellular metabolism and signalling. Critical Reviews in Plant Sciences 26: 17–43.