Tiny brain proteins shift in Alzheimer’s disease

Proteins are usually detected using standard molecular analysis techniques, but very small proteins (microproteins) often fall below detection thresholds. They are encoded by stretches of DNA long considered ‘non-coding’. New research published in Nature Aging now maps them systematically for the first time in the human frontal lobe.

The researchers identified 1,067 microproteins with high confidence scores in brain tissue from human donors. A subset of these microproteins showed differential expression in people with Alzheimer’s disease, independently of the larger canonical gene from which they are derived.

Mitochondria as a critical point

One of the most striking findings concerns a microprotein derived from the MKKS gene. This small protein appears necessary for normal energy production in mitochondria (the cell’s energy generators) within microglia, the brain’s resident immune cells. Microglia are known to play a role in Alzheimer’s progression. The finding that such a small protein directly affects the energy metabolism of these cells was previously unknown.

What the atlas offers

The atlas provides a new starting point for investigating mechanisms involved in Alzheimer’s. Most pharmacological approaches target well-characterised proteins such as amyloid-beta or tau. Microproteins have been largely ignored, partly because the techniques needed to detect them are still maturing. The researchers emphasise that this is a descriptive atlas: whether individual microproteins can serve as therapeutic targets requires further experimental work. From a longevity science perspective, it is notable that microproteins may play roles in brain aging more broadly, though that is not investigated in this study.

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