Phosphoproteomics Uncovers Exercise Intensity-Specific Skeletal Muscle Signaling Networks Underlying High-Intensity...

Area of Science:

• Exercise Physiology
• Molecular Biology
• Biochemistry

Background:

• Exercise engages protein kinases and signaling networks to manage metabolic demands and promote adaptations.
• High-intensity interval training (HIIT) offers time-efficient benefits for skeletal muscle and whole-body adaptations.
• The specific signaling pathways activated by HIIT in skeletal muscle remain largely uncharacterized.

Purpose of the Study:

• To map human muscle kinases, substrates, and signaling pathways activated or deactivated by acute high-intensity interval training (HIIT) compared to work-matched moderate-intensity continuous training (MICT).
• To identify exercise intensity-specific signaling responses in skeletal muscle.

Main Methods:

• A randomized crossover trial involving ten healthy males comparing single bouts of HIIT and MICT, matched for total work and duration.
• Muscle biopsy samples were collected pre-exercise, during (5 min), and immediately post-exercise (10 min).
• Mass spectrometry-based phosphoproteomic analysis was used to quantify changes in phosphorylation sites.

Main Results:

• Over 1000 differentially phosphorylated sites were identified in skeletal muscle following HIIT and MICT.
• HIIT induced more significant differential phosphorylation at 5 and 10 minutes compared to MICT (92 and 348 sites, respectively).
• Higher plasma lactate concentrations during HIIT correlated with over 3000 phosphosites, including those involved in metabolic regulation.

Conclusions:

• This study provides the first global map of work-matched HIIT versus MICT signaling networks in human skeletal muscle.
• Rapid, exercise intensity-specific regulation of kinases, substrates, and pathways was revealed.
• These findings may explain the superior skeletal muscle adaptations and health benefits associated with HIIT.