Interaction between signalling pathways involved in skeletal muscle responses to endurance exercise

Area of Science:

• Exercise Physiology
• Molecular Biology
• Skeletal Muscle Biology

Background:

• Endurance exercise induces significant adaptations in skeletal muscle.
• Transcriptional regulation of contractile and metabolic proteins is crucial for these adaptations.
• Understanding the signaling pathways involved is key to optimizing training and recovery.

Purpose of the Study:

• To review the latest literature on signaling pathways governing gene transcription in response to endurance exercise.
• To highlight the interplay between signaling pathways and myofiber phenotype.
• To focus on calcium-mediated signaling and its role in coordinating gene expression.

Main Methods:

• Literature review of signaling pathways in skeletal muscle during endurance exercise.
• Analysis of calcium-triggered regulatory pathways: calcineurin, Ca(2+)-calmodulin-dependent protein kinases (CaMK), and Ca(2+)-dependent protein kinase C.
• Examination of the role of peroxisome proliferator-activated receptor gamma (PPARgamma) coactivator-1alpha (PGC-1alpha).

Main Results:

• Calcium acts as a key second messenger, translating neuromuscular activity into gene transcription changes.
• Calcineurin signaling is vital for slow-fiber gene expression, impacting contractile function, calcium handling, and metabolism.
• PGC-1alpha is a central regulator coordinating mitochondrial biogenesis and coupling it with contractile and metabolic gene expression.

Conclusions:

• Calcium-dependent signaling pathways are critical for skeletal muscle adaptation to endurance exercise.
• Coordinated action of transcription factors and signaling cascades, including calcineurin and PGC-1alpha, dictates myofiber phenotype.
• Further research is needed to elucidate the integration of pathways like MAPK into the overall adaptive response.