TY - JOUR
T1 - Contribution of calpain Lp82-induced proteolysis to experimental cataractogenesis in mice
AU - Nakamura, Yoshikuni
AU - Fukiage, Chiho
AU - Shih, Marjorie
AU - Ma, Hong
AU - David, Larry L.
AU - Azuma, Mitsuyoshi
AU - Shearer, Thomas R.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 2000
Y1 - 2000
N2 - PURPOSE. The purpose of the present experiments was to provide a biochemical mechanism for the involvement of lens-specific calpain Lp82 in experimental cataractogenesis in mice. METHODS. Nuclear cataracts were produced by culturing lenses from 4-week-old mice and rats in calcium ionophore A23187 or by injection of buthionine sulfoximine (BSO) into 7-day- old mice. Casein zymography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblot analysis, calcium determinations, in vitro precipitation, and cleavage site analysis by mass spectrometry were performed on lens samples. RESULTS. Amino acid sequences for Lp82 were found to be highly conserved in lenses from mouse to cow, and expressed Lp82 proteolytic activity was high in the mouse and rat. Lenses from mice were more susceptible to A23187-induced cataract and BSO cataracts than rats. Both types of cataracts showed rapid elevation of calcium, activation of Lp82 and m-calpain, and proteolysis of crystallins. Lp82 caused in vitro precipitation of crystallins; and in contrast to m-calpain, Lp82 truncated only the first five amino acids from the C-terminus of αA-crystallin. CONCLUSIONS. Under pathologic conditions of massive elevation of lens calcium found in young rodent lenses, overactivation of Lp82 and m-calpain leads to rapid truncation of crystallins at both common and unique cleavage sites, precipitation of truncated crystallins, and cataract.
AB - PURPOSE. The purpose of the present experiments was to provide a biochemical mechanism for the involvement of lens-specific calpain Lp82 in experimental cataractogenesis in mice. METHODS. Nuclear cataracts were produced by culturing lenses from 4-week-old mice and rats in calcium ionophore A23187 or by injection of buthionine sulfoximine (BSO) into 7-day- old mice. Casein zymography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblot analysis, calcium determinations, in vitro precipitation, and cleavage site analysis by mass spectrometry were performed on lens samples. RESULTS. Amino acid sequences for Lp82 were found to be highly conserved in lenses from mouse to cow, and expressed Lp82 proteolytic activity was high in the mouse and rat. Lenses from mice were more susceptible to A23187-induced cataract and BSO cataracts than rats. Both types of cataracts showed rapid elevation of calcium, activation of Lp82 and m-calpain, and proteolysis of crystallins. Lp82 caused in vitro precipitation of crystallins; and in contrast to m-calpain, Lp82 truncated only the first five amino acids from the C-terminus of αA-crystallin. CONCLUSIONS. Under pathologic conditions of massive elevation of lens calcium found in young rodent lenses, overactivation of Lp82 and m-calpain leads to rapid truncation of crystallins at both common and unique cleavage sites, precipitation of truncated crystallins, and cataract.
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M3 - Article
C2 - 10798663
AN - SCOPUS:0034098098
SN - 0146-0404
VL - 41
SP - 1460
EP - 1466
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
IS - 6
ER -