Mitochondrial power grids in muscle

PainSci » bibliography » Glancy et al 2015
updated Oct 22, 2015

Tags: biology, muscle, neat

Two articles on PainSci cite Glancy 2015: 1. 38 Surprising Causes of Pain 2. A Painful Biological Glitch that Causes Pointless Inflammation

PainSci commentary on Glancy 2015: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.

For decades, mitochondria have been described as the “power plants” of cells, and they are already fascinating and complex. (I’m particularly amazed by their role in unnecessary inflammation.) But we may need to update the simile: turns out mitochondria don’t just produce energy “like a power plant,” they also deliver it like a network of power lines. This phenomenon was identified in mouse muscles:

Researchers found that mitochondria in mouse muscles not only produce energy, but can quickly distribute it across the muscle cell through a grid-like network. The findings reveal a major mechanism for energy distribution in skeletal muscle cells, and could provide new insights into diseases linked to energy use in muscle.

What a wonderful example of how much we still have to learn about muscle tissue (and others too, I’m sure, but muscle seems to be particularly full of surprising puzzles). It seems likely that we probably can’t understand muscle pain properly if we have only just now discovered something so fundamental about muscle biology. Imagine trying to troubleshoot an electrical problem if you weren’t aware of a major feature of how power is generated and transmitted!

~ Paul Ingraham

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

Intracellular energy distribution has attracted much interest and has been proposed to occur in skeletal muscle via metabolite-facilitated diffusion; however, genetic evidence suggests that facilitated diffusion is not critical for normal function. We hypothesized that mitochondrial structure minimizes metabolite diffusion distances in skeletal muscle. Here we demonstrate a mitochondrial reticulum providing a conductive pathway for energy distribution, in the form of the proton-motive force, throughout the mouse skeletal muscle cell. Within this reticulum, we find proteins associated with mitochondrial proton-motive force production preferentially in the cell periphery and proteins that use the proton-motive force for ATP production in the cell interior near contractile and transport ATPases. Furthermore, we show a rapid, coordinated depolarization of the membrane potential component of the proton-motive force throughout the cell in response to spatially controlled uncoupling of the cell interior. We propose that membrane potential conduction via the mitochondrial reticulum is the dominant pathway for skeletal muscle energy distribution.

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

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