title: Localization of calpain 3 in human skeletal muscle and its alteration in limb-girdle muscular dystrophy 2A muscle.
abstract: Calpain 3/p94, the skeletal muscle-specific isoform of the calpain large subunit family, is a protein product of the gene responsible for limb-girdle muscular dystrophy type 2A (LGMD2A). Through yeast two-hybrid experiments, calpain 3 has been shown to bind to titin in myofibrils [Sorimachi et al. (1995) J. Biol. Chem. 270, 31158-31162]. However, because of extensive autolysis activity, calpain 3 localization in skeletal muscle has been undefined. In this study, we generated a polyclonal antibody against an N-terminal 98-amino-acid calpain 3 fragment, which is not homologous to the corresponding regions of other conventional calpains. This antibody stained myofibrils with a unique repeated doublet-pattern. Confocal microscopic observation with marker antibodies confirmed that calpain 3 is localized in the N2 region of myofibrils. Furthermore, using this antibody, we examined the localization of calpain 3 in LGMD2A muscles.
authors.affiliation: Department of Neuromuscular Research, National Institute of Neuroscience, 4-1-1 Ogawahigashi, Kodaira, Tokyo 187-8502, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Keira
authors.forename: Satoru
authors.initials: S
authors.lastname: Noguchi
authors.forename: Narihiro
authors.initials: N
authors.lastname: Minami
authors.forename: Yukiko K
authors.initials: YK
authors.lastname: Hayashi
authors.forename: Ichizo
authors.initials: I
authors.lastname: Nishino
mesh_terms: D002154:Calpain / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007527:Isoenzymes; D018613:Microscopy, Confocal; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D009136:Muscular Dystrophies / Q000201:enzymology* / Q000473:pathology; D009210:Myofibrils / Q000737:chemistry / Q000201:enzymology / Q000648:ultrastructure; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D007527:Isoenzymes; D009124:Muscle Proteins; C105884:CAPN3 protein, human; D002154:Calpain