The ultrastructural localization of calpastatin, the endogenous inhibitor of the neutral calcium-dependent proteases (calpains), was investigated in rabbit skeletal muscle fibers using a polyclonal antibody against the 34 kDa form of the inhibitor isolated from rabbit. Quantitative studies by pre- and postembedding immunogold techniques revealed that the distribution pattern of the specific immunoreactivity included: 1) the sarcolemma with the adjacent cytoplasm (about 1 micron wide); 2) the myofibrils; 3) the mitochondria and 4) the nuclei (condensed as well as extended chromatin). Other cell substructures, such as lysosomes and the intermyofibrillar cytoplasm, were substantially devoid of immunoreactivity. Furthermore, in accordance to previous light microscope immunohistochemical experiments, an extracellular (endomysial) localization of specific immunoreactivity was confirmed. These results favour the view, which is also supported by a series of biochemical evidences, that calpastatin in rabbit skeletal muscle is present in cell structures also containing calpains and/or their putative substrates. The above multiple patterns of distribution also suggest that the muscular calpain-calpastatin system in skeletal muscle fibers may play different physiological roles in the various subcellular compartments.

Immunogold ultrastructural localization of calpastatin, the calpain inhibitor, in rabbit skeletal muscle / S. L., Nori; Pompili, Elena; DE SANTIS, Elena; G., De Renzis; A., Bondi; W. L., Collier; F., Ippoliti; Fumagalli, Lorenzo. - In: CELLULAR AND MOLECULAR BIOLOGY. - ISSN 0145-5680. - 39:7(1993), pp. 729-737.

Immunogold ultrastructural localization of calpastatin, the calpain inhibitor, in rabbit skeletal muscle.

POMPILI, Elena;DE SANTIS, Elena;FUMAGALLI, Lorenzo
1993

Abstract

The ultrastructural localization of calpastatin, the endogenous inhibitor of the neutral calcium-dependent proteases (calpains), was investigated in rabbit skeletal muscle fibers using a polyclonal antibody against the 34 kDa form of the inhibitor isolated from rabbit. Quantitative studies by pre- and postembedding immunogold techniques revealed that the distribution pattern of the specific immunoreactivity included: 1) the sarcolemma with the adjacent cytoplasm (about 1 micron wide); 2) the myofibrils; 3) the mitochondria and 4) the nuclei (condensed as well as extended chromatin). Other cell substructures, such as lysosomes and the intermyofibrillar cytoplasm, were substantially devoid of immunoreactivity. Furthermore, in accordance to previous light microscope immunohistochemical experiments, an extracellular (endomysial) localization of specific immunoreactivity was confirmed. These results favour the view, which is also supported by a series of biochemical evidences, that calpastatin in rabbit skeletal muscle is present in cell structures also containing calpains and/or their putative substrates. The above multiple patterns of distribution also suggest that the muscular calpain-calpastatin system in skeletal muscle fibers may play different physiological roles in the various subcellular compartments.
calpain inhibitor; calpastatin; calcium-activated neutral protease inhibitors; protease inhibitors; immunocytochemistry; skeletal muscle
01 Pubblicazione su rivista::01a Articolo in rivista
Immunogold ultrastructural localization of calpastatin, the calpain inhibitor, in rabbit skeletal muscle / S. L., Nori; Pompili, Elena; DE SANTIS, Elena; G., De Renzis; A., Bondi; W. L., Collier; F., Ippoliti; Fumagalli, Lorenzo. - In: CELLULAR AND MOLECULAR BIOLOGY. - ISSN 0145-5680. - 39:7(1993), pp. 729-737.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/243352
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