Scientists map 4,321 brain microproteins in largest Alzheimer's atlas

September 16, 2026 at 01:47 PM2 min

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Researchers identified 4,321 microproteins in postmortem human brain tissue, creating the largest atlas of microproteins in Alzheimer's disease to date. The study, published in Nature Aging on 14 September, found altered expression of dozens of microproteins in people with Alzheimer's disease. The findings could reveal new mechanisms of ageing and neurodegeneration.

Key Facts

The study identified 4,321 microproteins in 608 postmortem brain samples from individuals with and without Alzheimer's disease.
3,217 of the identified microproteins had not been previously characterized in the UniProtKB/Swiss-Prot catalogue.
Dozens of microproteins showed altered expression in people with Alzheimer's disease.
The research was published in Nature Aging on 14 September.

Microprotein Detection Challenge

Microproteins are small proteins with fewer than 150 amino acids and are notoriously difficult to detect with standard gene and protein sequencing techniques. Because of their short length, the standard method to identify the protein content of cells, known as mass spectrometry, often fails to detect them. Some microproteins are made by parts of the genome that were thought to be non-coding and unable to produce proteins, while others are made from coding genes that also produce large, known proteins. This has made it difficult to find microproteins using conventional RNA sequencing techniques.

Study Methodology

To overcome these challenges, Miller and his colleagues used a combination of mass spectrometry, RNA sequencing and ribosomal profiling. Ribosomal profiling involves collecting all ribosomes — the cellular machines that build proteins from RNA — in each cell and sequencing the individual strands of messenger RNA that are bound to them. Using this approach, the team analysed 608 postmortem brain samples from individuals with and without Alzheimer's disease. They identified 4,321 microproteins, 3,217 of which had not been previously characterized in a standard catalogue of human proteins called UniProtKB/Swiss-Prot.

Alzheimer's Disease Implications

Dozens of the tiny proteins showed altered expression in people with Alzheimer's disease, which could pave the way to unlocking new mechanisms of ageing and neurodegeneration. Bahareh Ajami, a neuroimmunologist at Cedars-Sinai Medical Center in Los Angeles, California, said that researchers might be missing a whole layer of biology by overlooking these microproteins. Study co-author Brendan Miller, a neuroscientist at the Salk Institute for Biological Studies in San Diego, California, said that Alzheimer's disease is a proteinopathy wherein the pathology is in part due to proteins that have misfolded or accumulated and evoked a toxic response. Miller added that it should be somewhat urgent to understand the full proteome, including microproteins.