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Updated: Mar 24, 2026

Quantifying Tissue-Specific Proteostatic Decline in Caenorhabditis elegans
Published on: September 7, 2021
Calcium and calpastatin delay proteolysis early during beef maturation
J S Bodmer1, M Beline2, C N Yen3
1Department of Animal and Dairy Sciences, Mississippi State University, Mississippi State, MS 39762, USA.
Abstract:
This study extends our investigation of calpain-mediated proteolysis during early beef maturation using an in vitro proteolytic approach. Calpain-1 autolysis and calpastatin abundance were determined in the Longissimus thoracis et lumborum (LTL) and Extensor carpi radialis (ER) muscles of carcasses aged 0, 1, 2, 7, and 14 d postmortem. Samples were powdered and added to myofibrils in an in vitro digestion protocol. Aliquots were collected at 0, 120, 480, and 1440 min of incubation, and calpain-1 autolysis, calpastatin, and desmin degradation were determined. Calcium was added to determine the impact of free calcium on in vitro proteolysis at 0 and 1 d LTL. In the absence of added calcium, 0 d LTL digestions retained (P < 0.001) higher levels of intact 80 kDa calpain-1 across all timepoints, while digestions containing 7 and 14 d LTL had the highest (P < 0.001) ratios of the 76 kDa subunit. In the presence of added calcium, 0 and 1 d LTL increased (P < 0.001) the autolysis of the 80 kDa subunit (P < 0.001). Addition of calcium facilitated greater (P < 0.027) desmin degradation in 1 d LTL but not in 0 d LTL. Approximately, 25% of intact calpastatin remained in the 1 d LTL carcass timepoint, whereas 50% of intact calpastatin remained present in the ER until 2 d. ER exhibited minimal proteolysis across all timepoints analyzed. These findings suggest both calcium availability and calpastatin may limit calpain-1 activity in the first 24 h postmortem in a muscle-dependent manner.
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