Neurons have developed elaborate mechanisms for transporting critical components, like transmitter-laden vesicles, down their axons to the synaptic terminations. An axon in a blue whale may be several meters long while those in M.mymaripenne, a wasp smaller than a paramecium, may be just microns long. Yet regardless of scale, these axons all seem to use similar molecular motors working on similar microtubule tracks to deliver vesicular cargo. In a paper recently published in Cell, researchers at INSERM, in France, have shown that the principle source of energy for these motors may not be the mitochondria as has been traditional assumed. Instead the ATP to power these motors appears to from vesicle-attached glycoloytic machinery, namely the enzyme GADPH (Glyceraldehyde 3-phosphate dehydrogenase).
In physics, the principle of conservation of energy (momentum as well) provides a way to solve many complex problems. Similarly in neurons, often the best way to try figure out how a particular mechanism works, is to analyze how the energy for it is sourced and dissipated. The INSERM researchers, who have studied the role of mitochondria in diseases like Huntington’s disease in the past, noted that degeneration of axons is a principle pathology. In particular, they sought to find out whether the observed degeneration could be due to insufficient energy to power axonal transport. Curiously, they found that inhibiting the function of mitochondria, and hence the cell’s main energy source, had no effect on the transport of vesicles.
Read more at: medicalXpress.com