We have recently demonstrated that in resting conditions calpain 1, but not calpain 2, is specifically associated to the N-Methyl-D-Aspartate receptor (NMDAR) multiprotein complex. We are here reporting that in SKNBE neuroblastoma cells or in freshly isolated nerve terminals from adult rat hippocampus, the proteolytic activity of calpain 1 resident at the NMDAR is very low under basal condition...

Two forms of pig kidney calpain II were isolated, both of which appeared to contain an intact 80 kDa large subunit, but which showed specific proteolytic degradation at the N-terminal end of the 30 kDa small subunit. The structure of each of these molecules was investigated by amino acid sequence analysis. The forms corresponded to molecules with small subunits starting at residue 38 (degraded ...

Regulating the balance between synthesis and proteasomal degradation of cellular proteins is essential for tissue growth and maintenance, but the critical pathways regulating protein ubiquitination and degradation are incompletely defined. Although participation of calpain calcium-activated proteases in post–necrotic myocardial autolysis is well characterized, their importance in homeostatic tu...

OBJECTIVE We tested the hypothesis of a role for the calcium-dependent protease calpain in the endothelial dysfunction induced by hyperglycemic activation of protein kinase C (PKC). METHODS AND RESULTS Chronic hyperglycemia with insulin deficiency (type 1 diabetes) was induced in rats by streptozotocin. Total PKC and calpain activities, along with activity and expression level of the 2 endoth...

Interaction of integrins with the extracellular matrix leads to transmission of signals, cytoskeletal reorganizations, and changes in cell behavior. While many signaling molecules are known to be activated within Rac-induced focal complexes or Rho-induced focal adhesions, the way in which integrin-mediated adhesion leads to activation of Rac and Rho is not known. In the present study, we identi...

Muscle wasting in sepsis is a significant clinical problem because it results in muscle weakness and fatigue that may delay ambulation and increase the risk for thromboembolic and pulmonary complications. Treatments aimed at preventing or reducing muscle wasting in sepsis, therefore, may have important clinical implications. Recent studies suggest that sepsis-induced muscle proteolysis may be i...

Proteases as well as alterations in intracellular calcium have important roles in hepatic preservation-reperfusion injury, and increased calpain activity recently has been demonstrated in liver allografts. Experiments were designed to evaluate (i) hepatic cytosolic calpain activity during different periods of cold ischemia (CI), rewarming, or reperfusion, and (ii) effects of inhibition of calpa...

Tenderness is a key component of palatability, which influences consumers’ perception of meat quality. There are a variety of factors that contribute to variations in tenderness, including postmortem proteolysis. A more complete understanding of this biological mechanism regulating tenderness is needed to ensure consistently tender beef. Numerous reports indicate μ-calpain is primarily responsi...

Gallbladder carcinoma (GBC) possesses a poor prognosis, which is primarily attributed to the lack of early and timely surgical intervention. Calpain-1 and glypican-3 have been implicated in the progression of various types of cancer. The present study aimed to detect the expression of calpain-1 and glypican-3 in GBC, and analyzed whether the expression levels of these proteins correlated with a...

PURPOSE Activation of calpains (calpain 2 and Lp82) in rodent lenses readily causes proteolysis and cataract formation. In contrast, primate lenses are quite resistant to activation of calpains. The hypothesis is that high levels of human endogenous calpain inhibitor, calpastatin (CS), prevent calpain activation in human lenses. The purpose of the present study was to directly test if CS is a m...