CAPN3
Calpain-3 (EC 3.4.22.54) (Calcium-activated neutral proteinase 3) (CANP 3) (Calpain L3) (Calpain p94) (Muscle-specific calcium-activated neutral protease 3) (New calpain 1) (nCL-1) [CANP3] [CANPL3] [NCL1]
Publications[править]
Mutations in CAPN3 gene cause limb-girdle muscular dystrophy type 2A (LGMD2A) characterized by muscle wasting and progressive degeneration of scapular and pelvic musculature. Since CAPN3 knockout mice (C3KO) display features of muscle pathology similar to those features observed in the earliest-stage or preclinical LGMD2A patients, gene expression profiling analysis in C3KO mice was performed to gain insight into mechanisms of disease. Two different comparisons were carried out in order to determine, first, the differential gene expression between wild-type (WT) and C3KO soleus and, second, to identify the transcripts differentially expressed in aging muscles of WT and C3KO mice. The up/downregulation of two genes, important for normal muscle function, was identified in C3KO mice: the Ky gene, encoding a protease implicated in muscle development, and Park2 gene encoding an E3 ubiquitin ligase (parkin). The Ky gene was downregulated in C3KO muscles suggesting that Ky protease may play a complementary role in regulating muscle cytoskeleton homeostasis in response to changes in muscle activity. Park2 was upregulated in the aged WT muscles but not in C3KO muscles. Taking into account the known functions of parkin E3 ligase, it is possible that it plays a role in ubiquitination and degradation of atrophy-specific and damaged proteins that are necessary to avoid cellular toxicity and a cellular stress response in aging muscles.
MeSH Terms
- Aging
- Animals
- Calpain
- Gene Expression Profiling
- Gene Expression Regulation
- Humans
- Male
- Mice
- Mice, Knockout
- Muscle Proteins
- Muscle, Skeletal
- Muscular Dystrophies, Limb-Girdle
- Mutation
- Peptide Hydrolases
- Ubiquitin-Protein Ligases
Previous studies have demonstrated that in 129alpha3Cx46-/- mice, age-related nuclear cataract is formed. In the present study, a more in vivo-relevant model was generated to test the hypothesis that the calpain 3 gene is involved in age-related nuclear cataractogenesis in alpha3Cx46 knockout mice. To test the hypothesis that the calpain 3 gene is involved in age-related nuclear cataractogenesis in alpha3Cx46 knockout mice, 129alpha3Cx46-/- and CAPN3-/- mice were mated to generate homozygous double-knockout (dKO) mice. Lenses from the mice were examined by visual observation, laser scan analysis, and histologic and biochemical methods. In the absence of the CAPN3 gene, the formation of a cataract was delayed, and its appearance was changed to a more diffuse, pulverulent type. Unlike in the 129alpha3Cx46-/- mouse, cleavage of gamma-crystallin was not detected in the dKO mouse. In both 129alpha3Cx46-/- and dKO mice, total Ca2 increased. The present study shows for the first time that calpain 3 is necessary for the formation of age-dependent nuclear cataracts in alpha3Cx46-/- mice. Evidence that the calpain 3 gene is directly involved in, or part of the pathway that leads to, gamma-crystallin cleavage is presented. These results are consistent with the hypothesis that the loss of alpha3Cx46 leads to increased levels of Ca2 ions, and this increase activates the CAPN3 isoform, Lp82/85, which results in the formation of a nuclear cataract.
MeSH Terms
- Aging
- Animals
- Blotting, Western
- Body Water
- Calcium
- Calpain
- Cataract
- Connexins
- Female
- Genotype
- Lens, Crystalline
- Male
- Mice
- Mice, Knockout
- Mice, Transgenic
- Muscle Proteins
- Organ Culture Techniques
- Organ Size
- Protein Isoforms
- gamma-Crystallins