Recent Data on Cellular Component Turnover: Focus on Adaptations to Physical Exercise.

Area of Science:

• Muscle physiology and cellular biology
• Exercise science and adaptation
• Molecular mechanisms of protein turnover

Background:

• Muscle protein turnover is vital for adapting to exercise.
• Signaling pathways like AMPK, FOXO, and MTOR regulate cellular maintenance.
• Autophagy and mitophagy are critical for organelle quality control during exercise.

Purpose of the Study:

• To review mechanisms governing cellular component turnover during exercise.
• To discuss the role of these mechanisms in exercise training adaptations.
• To highlight emerging pathways and their implications for muscle health.

Main Methods:

• Literature review of recent studies on muscle protein turnover and exercise.
• Analysis of signaling pathways including AMPK, FOXO, and MTOR.
• Discussion of cellular trafficking, organelle turnover, and flux assessments.

Main Results:

• AMPK, FOXO, and MTOR are central to autophagy and organelle maintenance during exercise.
• Lysosomal trafficking is key for MTOR activation and protein synthesis during recovery.
• Parkin, Mul1, and DAG pathways are involved in organelle and protein turnover.
• Autophagy and mitophagy provide insights into mitochondrial turnover in aging and chronic exercise.

Conclusions:

• Further research is needed to clarify autophagy's role in complex exercise conditions (e.g., hypoxia) and different exercise modalities in humans.
• Understanding these pathways can lead to therapeutic strategies for muscle disorders.
• This review synthesizes current knowledge on exercise-induced muscle protein turnover mechanisms.