Summary: A new method identifies which proteins in human muscle cells are most important for increasing sugar uptake after exercise, improving our understanding of how exercise helps regulate blood sugar.
Source: University of Sydney
An international team of researchers has developed a precise, protein-focused method to determine which cellular proteins drive the improved sugar absorption that follows exercise—an effect that supports healthy blood glucose control.
Published in the December issue of the peer-reviewed journal Nature Biotechnology, this work represents a collaboration between scientists at the University of Sydney and the University of Copenhagen. Using advanced mass spectrometry, the team measured phosphorylation patterns directly in human skeletal muscle to reveal how exercise and insulin interact at the molecular level.
By profiling proteins across individuals, the researchers found that each person has a distinct phosphoproteomic “fingerprint”: a unique pattern of protein modifications that varies between people and mirrors differences in how their muscles absorb sugar.
The new personalized approach identifies specific phosphorylation changes that co-vary with measured improvements in sugar uptake after exercise. Those linked phosphosites mark proteins and pathways most likely to control the beneficial metabolic response.
Using this strategy, the team uncovered a mechanism revealing how exercise boosts muscle glucose uptake after insulin stimulation, offering clearer insight into a complex signaling network that supports blood sugar regulation.
“Exercise is broadly beneficial, and one important effect is that it enhances muscle glucose uptake following a meal,” said senior co-author Professor David James, ARC Laureate and Leonard P. Ullmann Chair of Metabolic Systems Biology at the Charles Perkins Centre and the University of Sydney. “When this process is impaired—commonly referred to as prediabetes—it raises the risk of conditions such as type 2 diabetes, heart disease, and some cancers. Understanding which molecular signals matter most is critical for developing interventions that prevent disease before it progresses.”
Opening protein ‘doors’ to sugar
Muscle glucose uptake relies on a coordinated set of proteins. The sequence begins when insulin binds receptors on the surface of muscle and fat cells, triggering thousands of intracellular phosphorylation events—chemical tags added to proteins that change their activity. These phosphorylation cascades ultimately open protein “doors” that allow glucose to enter cells.
Many phosphorylation signals are altered in prediabetes, but before this work it was unclear which specific phosphosites and pathways are the most important targets to restore healthy glucose handling.
Lead author Elise Needham, a Ph.D. candidate at the University of Sydney, explained the difficulty: “Exercise changes thousands of phosphorylation events. Distinguishing the key functional signals from background variation has been a major challenge.”
To address this, the team developed “personalized phosphoproteomics,” an approach that combines high-resolution experimental measurements with computational analysis that leverages natural differences between individuals. By comparing each person’s phosphoproteome response to exercise with their measured glucose uptake, the researchers linked molecular changes to functional outcomes.
“Inter-individual variation in phosphorylation behaves like a molecular fingerprint,” said senior co-author Dr. Sean Humphrey of the Charles Perkins Centre. “Rather than treating that variation as noise, our method uses it to reveal which phosphorylation events consistently track with improved glucose uptake.”
Applying personalized phosphoproteomics, the researchers identified both previously known and novel phosphosites on proteins involved in glucose metabolism. Notably, they found evidence of interplay between two key metabolic regulators—mTOR and AMPK—showing that mTOR can directly phosphorylate AMPK on S377, a modification implicated in metabolic control.
These findings refine our understanding of how exercise primes muscle to respond to insulin and highlights candidate molecular switches that could be targeted to prevent or treat impaired glucose regulation.
Beyond exercise physiology and glucose metabolism, the research team anticipates that personalized phosphoproteomics will be broadly useful for uncovering causal signaling changes in many complex diseases. By comparing diseased and healthy cells at the level of individual phosphosites and linking those differences to functional outcomes, researchers can prioritize the most relevant molecular targets for therapeutic development.
About this exercise research news
Author: Press Office
Source: University of Sydney
Contact: Press Office – University of Sydney
Image: The image is credited to Elise Needham
Original Research: Closed access. “Personalized phosphoproteomics identifies functional signaling” by Elise J. Needham et al., Nature Biotechnology.
Abstract
Personalized phosphoproteomics identifies functional signaling
Protein phosphorylation dynamically integrates environmental and cellular information to control biological processes. Identifying which phosphorylation events are functionally important among the thousands of regulated phosphosites after a stimulus is a major challenge.
Here the authors introduce “personalized phosphoproteomics,” combining experimental and computational analyses that link signaling changes with biological function by exploiting natural human phenotypic variation. By measuring individual phosphoproteome responses to interventions alongside matched phenotypic measurements, and applying this to how exercise potentiates insulin signaling in human skeletal muscle, the study identifies known and novel phosphosites on proteins involved in glucose metabolism. The results include a cooperative relationship between mTOR and AMPK, with mTOR phosphorylating AMPK at S377 and a role for this modification in metabolic regulation.
These findings establish personalized phosphoproteomics as a general approach for investigating the signal transduction mechanisms that underlie complex biological responses and disease-relevant phenotypes.