Interaction between myoglobin and mitochondria in rat skeletal muscle

Abstract

The mechanisms underlying subcellular oxygen transport mediated by myoglobin (Mb) remain unclear. Recent evidence suggests that, in the myocardium, transverse diffusion of Mb is too slow to effectively supply oxygen to meet the immediate mitochondrial oxygen demands at the onset of muscle contractions. The cell may accommodate the demand by maintaining the distribution of Mb to ensure a sufficient O(2) supply in the immediate vicinity of the mitochondria. The present study has verified the co-localization of Mb with mitochondria by using biochemical histological and electron microscopy analyses. Immunohistochemical and electron microscopy analysis indicates a co-localization of Mb with mitochondria. Western blotting confirms the presence of Mb colocalizes with the mitochondrial fraction and appears more prominently in slow-twitch oxidative than in fast-twitch glycolytic muscle. In particular, Mb interacts with cytochrome c oxidase-subunit IV. These results suggest that a direct Mb-mediated O2 delivery to the mitochondria, which may play a potentially significant role for respiration.

Effects of an 8-weeks erythropoietin treatment on mitochondrial and whole body fat oxidation capacity during exercise in healthy males

“…The discrepancy with our results may be explained by the application of different techniques to assess myoglobin levels (protein concentration vs. mRNA expression), the different time points selected to measure the gene expression of myoglobin, and the fact that maybe a single acute infusion of recombinant erythropoietin does not provide sufficient stimulus to produce a positive myoglobin mRNA expression. Studies performed in rats support our results, by co-localisation of myoglobin and mitochondrial complex IV, which suggest a direct myoglobin-mediated O 2 delivery to the mitochondria that in turn may play a potentially significant role for respiration (Yamada et al, 2013). In consequence, more studies to further elucidate the potential role of myoglobin on the skeletal muscle Erythropoietin and muscle mitochondrial respiration 7 adaptations to a recombinant erythropoietin treatment are needed.…”

Novel Molecular Interactions of Acylcarnitines and Fatty Acids with Myoglobin

“…through site-directed mutagenesis). Interestingly, recent studies indicate that oxy-Mb interacts with mitochondria in the muscle cells, initiating a conformational change in the oxy-Mb during the release of oxygen (40,41). These results must be taken into account in future studies of the retention of fatty acids or acylcarnitines when bound to oxy-Mb that may simultaneously release both oxygen and lipids to the mitochondria.…”

High fatty acid oxidation capacity and phosphorylation control despite elevated leak and reduced respiratory capacity in northern elephant seal muscle mitochondria

“…The vast majority of myoglobin is leached from fibers during the preparation and permeabilization procedure to avoid confounding effects on O 2 transport. However, we cannot rule out potentially additive effects of myoglobin on NES muscle fatty acid oxidation capacity in vivo, nor a potential contribution of trace levels that might remain in specialized cellular compartments, such as bound to mitochondria (Yamada et al, 2013), following fiber permeabilization in our experiments. A previous study in Weddell seals demonstrated a paradoxical decrease in muscle mitochondrial volume density as seals reached maturity, despite evidence for improved aerobic exercise capacity to sustain longer and deeper dives in adulthood (Kanatous et al, 2008).…”