Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.22.54 (calpain 3)
430 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calcium dependent proteases (calpains, CAPNs, E.C.3.4.22.17) constitute a family of proteins which share a homologous cysteine-protease domain (large subunits, L1, L2, and L3) and an E-F hand Ca2(+)-binding domain (L1, L2, L3, and small subunit, S). We have mapped the genes for four calpain proteins (L1, L2, L3, and S) on four distinct human chromosomes by a combination of spot-blot hybridization to flow-sorted chromosomes and Southern hybridization of DNAs from a human x mouse hybrid cell panel. The genes for calpain L1 (CAPN1, large subunit of calpain I), L2 (CAPN2, large subunit of calpain II), L3 (CAPN3, a protein related to the large subunits), and S (CAPN4, a small subunit common to calpains I and II) were assigned to human chromosomes 11, 1, 15, and 19, respectively.
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PMID:Four genes for the calpain family locate on four distinct human chromosomes. 220 92

In the course of cDNA cloning of the large subunits of human mu- and mCANPs, a novel cDNA clone encoding a putative calcium-dependent cysteine protease homologous to but distinct from both mu- and m-types was found. The encoded protein, designated tentatively as p94, is composed of four domains similar to those found in other CANP large subunits, but includes three unique regions that have no homology to other CANPs. These unique sequences might be involved in regulating the activation and/or determining the intracellular localization of p94. Since the mRNA for p94 is five times more abundant than that for the CANP small subunit in skeletal muscle, it is possible that p94 does not associate with the small subunit in vivo. In contrast to the ubiquitous expression of mu- and m-types, the mRNA for p94 is expressed only in skeletal muscle. Besides acting as a protease, p94 may act as a skeletal muscle specific regulatory protein like troponin C.
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PMID:A novel member of the calcium-dependent cysteine protease family. 240 May 79

A calcium-activated neutral proteinase (CANP) was prepared from the soluble fraction of calf thymus and purified to electrophoretical homogeneity. The purified proteinase was shown to consist of two subunits, each of 80 kDa, in contrast to rabbit skeletal muscle calpain which was shown to consist of 80 kDa and 30 kDa subunits. The calcium requirement for 50% activation was 0.55 mM, indicating that this enzyme belongs to the low calcium sensitive type CANP, named mCANP or Calpain II. Optimal conditions of enzyme activity towards 0.8% casein as substrate are pH 7.5, a calcium concentration of 1.5 mM, the presence of an SH-reducing agent and an incubation temperature of 30 degrees C. The enzyme is inhibited by Zn2+, p-chloromercuribenzoate and N-ethylmaleimide.
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PMID:Purification and characterization of calcium-activated neutral proteinase from calf thymus. 285 33

Recent studies indicate that calpain, a cytosolic Ca2+-dependent protease, constitutes a large family comprising ubiquitous, tissue-specific, and atypical calpains. p94 is a homologue of the catalytic large subunit of calpain, expressed predominantly in skeletal muscle. Recently, p94 has been found to interact with connectin/titin, a muscle elastic protein, and its gene has been identified as being responsible for limb-girdle muscular dystrophy type 2A. The loss of function of a calpain species eventually leads to the activation of proteases including other calpain species responsible for muscle degradation. p94 does not form a complex with the small subunit of calpain (30K), but exists as a homodimer. This, together with other results, led us to consider a novel mechanism for the activation of calpain, a Ca2+-induced subunit rearrangement.
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PMID:Skeletal muscle-specific calpain, p49: structure and physiological function. 976 16

The ubiquitous calpains, calpain-1 and -2, play important roles in Ca²⁺-dependent membrane repair. Mechanically active tissues like skeletal muscle are particularly reliant on mechanisms to repair and remodel membrane injury, such as those caused by eccentric damage. We demonstrate that calpain-1 and -2 are master effectors of Ca²⁺-dependent repair of mechanical plasma membrane scrape injuries, although they are dispensable for repair/removal of small wounds caused by pore-forming agents. Using CRISPR gene-edited human embryonic kidney 293 (HEK293) cell lines, we established that loss of both calpains-1 and -2 (CAPNS1^-/-) virtually ablates Ca²⁺-dependent repair of mechanical scrape injuries but does not affect injury or recovery from perforation by streptolysin-O or saponin. In contrast, cells with targeted knockout of either calpain-1 (CAPN1^-/-) or -2 (CAPN2^-/-) show near-normal repair of mechanical injuries, inferring that both calpain-1 and calpain-2 are equally capable of conducting the cascade of proteolytic cleavage events to reseal a membrane injury, including that of the known membrane repair agent dysferlin. A severe muscular dystrophy in a murine model with skeletal muscle knockout of Capns1 highlights vital roles for calpain-1 and/or -2 for health and viability of skeletal muscles not compensated for by calpain-3 (CAPN3). We propose that the dystrophic phenotype relates to loss of maintenance of plasma membrane/cytoskeletal networks by calpains-1 and -2 in response to directed and dysfunctional Ca²⁺-signaling, pathways hyperstimulated in the context of membrane injury. With CAPN1 variants associated with spastic paraplegia, a severe dystrophy observed with muscle-specific loss of calpain-1 and -2 activity identifies CAPN2 and CAPNS1 as plausible candidate neuromuscular disease genes.
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PMID:Loss of calpains-1 and -2 prevents repair of plasma membrane scrape injuries, but not small pores, and induces a severe muscular dystrophy. 3234 80

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