In skeletal muscle during intense chronic stress, why does protein degradation via the ubiquitin-proteasome pathway (UPP) accelerate relative to protein synthesis?

💡 Explanation

Chronic stress increases glucocorticoid levels, which upregulate E3 ubiquitin ligases like MuRF1 and atrogin-1, accelerating UPP-mediated protein breakdown because these enzymes tag proteins for degradation. Therefore, muscle protein degradation increases rather than protein synthesis because of the hormonal stress response.

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