Muscular activities promote a cascade of signals leading to the stimulation of eukaryotic initiation of myofibrillar protein synthesis. Nitrogen balance (difference between protein intake and protein degradation) for athletes is usually balanced when the intake of protein reaches 1.2 g Endurance exercise induces a greater oxidative capacity (enzymes) compared to resistance exercise, which induces fiber hypertrophy (myofibrils). Individuals who exercise respond differently when resistance and endurance types of contractions are compared. Strenuous exercise provokes increased proteolysis and decreased protein synthesis, the opposite occurring during the recovery period. There are different fractional synthesis rates in skeletal muscle and tendon tissues, but there is no major difference between collagen and myofibrillar protein synthesis. a transmembrane protein (TMEM251) selec-tively required for cell survival and growth when extracellular proteins were an obliga-tory amino acid source. More synthesis than breakdown indicates an.

A balance between protein synthesis and protein degradation is required for good health and normal protein metabolism. Different types of proteins have very different turnover rates. Drosophila is the most powerful invertebrate model with well-differentiated tissues, including brain, eye, heart, somatic stem cells and kidney-related tissues. In cell biology, protein turnover refers to the replacement of older proteins as they are broken down within the cell. Stable isotopic tracers ((13)C-lysine, (15)N-glycine, ²H5-phenylalanine) and arteriovenous differences have been used in studies of skeletal muscle and collagen tissues under resting and exercise conditions. Drosophila has several advantages that make it an ideal system for in vivo analysis of protein and mitochondrial turnover during aging. Noninvasive and invasive techniques have been applied to determine amino acid catabolism and muscle protein building at rest, during exercise and during the recovery period after a single experiment or training sessions. As for any cell or tissue, total muscle protein reflects a dynamic turnover between net protein synthesis and degradation. Skeletal muscle is the major deposit of protein molecules. The simplest model of protein turnover assumes that synthesis is a zero-order process and degradation is a first-order process.

Protein turnover ibmk