Disease relevance of CAST

• To investigate whether CSE-induced inhibition of eNOS gene expression is caused by decreased calpain activity due to an increase in calpastatin protein content, we cloned calpastatin gene from PAEC and constructed adenovirus vectors containing calpastatin [1].
• Analysis of structure-function relationship of pig calpastatin by expression of mutated cDNAs in Escherichia coli [2].
• beta-Adrenergic agonists induce muscle hypertrophy in mammalian species and alter the extractable activity of calpain proteinase and its specific endogenous inhibitor calpastatin [3].
• Calpastatin activity; mu-calpain activity; and autolysis and proteolysis of titin, nebulin, desmin, and troponin-T were determined on muscle samples from the LD, SM, and PM at early times postmortem [4].

High impact information on CAST

• Amino-terminal conserved region in proteinase inhibitor domain of calpastatin potentiates its calpain inhibitory activity by interacting with calmodulin-like domain of the proteinase [5].
• Calpastatin is an endogenous inhibitor protein specifically acting on calpains (Ca2+-dependent cysteine endopeptidases) [2].
• We recently cloned and sequenced the cDNA for pig heart calpastatin and determined the amino acid sequence of the molecule from the nucleotide sequence [2].
• The central region contains a 12-residue consensus sequence common to Domains 1, 2, and 4, and this portion is predicted to be located on the surface of the calpastatin molecule [2].
• In this study, we evaluated the role of calpain-calpastatin in CSE-induced decrease in eNOS gene expression [1].

Biological context of CAST

• Mapping of calpastatin and three microsatellites to porcine chromosome 2q2.1-q2.4 [6].
• Three polymorphisms were identified in a 1.6-kb fragment of the porcine calpastatin (CAST) gene and these polymorphisms were used for genetic linkage mapping [6].
• Studies of the active site of m-calpain and the interaction with calpastatin [7].
• The interaction of calpain with calpastatin was investigated using an assay based on binding to calpastatin-Sepharose and a competitive binding assay [7].
• The amino acid sequence deduced from the nucleotide sequence revealed the occurrence of a repetitive sequence at the interval of 140 amino acids, substantiating the multidomain structure of calpastatin [8].

Anatomical context of CAST

• The cell-permeable calpain inhibitor, calpastatin peptide, inhibits acetylcholine-induced endothelium-dependent relaxation of the pulmonary artery [1].
• The present study does not conclude, however, whether or not the 68 kDa calpastatin found in erythrocytes is a derived product from the 107 kDa species, which is present as such in heart muscle [9].
• Effects of epinephrine infusion on expression of calpastatin in porcine cardiac and skeletal muscle [3].
• Epinephrine infusion had no effect on skeletal calpastatin mRNA but tended to increase the 5.8-kb mRNA in cardiac muscle (P = 0. 053) [3].
• Transient transfection assays in both a non-fusing skeletal muscle and non-muscle cell-line demonstrated that the putative porcine calpastatin promoter regions 5' to exons 1xa, 1xb, and 1u were functional [10].

Associations of CAST with chemical compounds

• Pig heart calpastatin: identification of repetitive domain structures and anomalous behavior in polyacrylamide gel electrophoresis [11].
• The calculated molecular weight of pig calpastatin of 713 amino acid residues (Mr 77,122) is significantly lower than the value of purified pig heart calpastatin (Mr 107,000) estimated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) [11].

Regulatory relationships of CAST

• Both calpain I and calpain II were inhibited by calpastatin [12].

Other interactions of CAST

• Two forms of Ca2+-dependent cysteine proteinase (calpain, EC 3.4.22.17) and their specific endogenous inhibitor (calpastatin) were partially purified from porcine retina: calpain I (low-Ca2+-requiring form) was half-maximally activated at 8 microM-Ca2+, and calpain II (high-Ca2+-requiring form) at 250 microM-Ca2+ [12].

Analytical, diagnostic and therapeutic context of CAST

• It is most likely that the discrepancy in the molecular weight is caused by an anomalous behavior of calpastatin in SDS-PAGE [11].
• Left ventricular tissue was collected after recovery and analyzed by Western blot for TnI, calpain, and calpastatin (the natural inhibitor of calpain) [13].
• Glucocorticoids preserve calpastatin and troponin I during cardiopulmonary bypass in immature pigs [13].
• Reduction in reperfusion injury by glucocorticoids may depend partly on preservation of calpastatin activity and intact TnI [13].
• From Northern blots, the patterns of calpastatin mRNA species were similar in the two muscle types, two major transcripts at 5.8 and 3 [3].

References