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Modelling cortical cataractogenesis XXIX. Calpain proteolysis of lens fodrin in cataract
Author(s) -
Kilic Fusun,
Trevithick John R.
Publication year - 1998
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1002/iub.7510450514
Subject(s) - calpain , proteolysis , lens (geology) , biophysics , actin , chemistry , cytoskeleton , enzyme , biochemistry , biology , cell , paleontology
The relation between cataract and calpain proteolysis of lens fodrin was studied in two systems: elevated glucose (55.6 mM, diabetic model), and cytochalasin D (CD, 10 ‐2 mM, actin depolymerization‐induced opacity model). Glucose treatment (48 h) caused a visible opaque layer and enzyme leakage, with a concomitant accumulation of ([Ca2+] i ) around the lens equatorial cortex. CD caused both earlier and greater opacity and enzyme leakage than glucose. Lens fodrin digestion occurred in parallel with the timing and extent of calcium elevation. A calpain inhibitor peptide (CIP, 10 ‐2 mM) reduced the proteolysis of fodrin, opacity, and enzyme leakage in glucose‐treated lenses but only partially retarded them in CD‐treated lenses. These results suggest a mechanism in which calpain proteolysis of fodrin is a critical event in lens damage during opacification of cortical cataract.