Article: article from journal or magazin.
Amyloid and non-amyloid forms of 5q31-linked corneal dystrophy resulting from kerato-epithelin mutations at Arg-124 are associated with abnormal turnover of the protein.
The Journal of biological chemistry
Publication types: Journal Article ; Research Support, Non-U.S. Gov't - Publication Status: ppublish
Mutations in kerato-epithelin are responsible for a group of hereditary cornea-specific deposition diseases, 5q31-linked corneal dystrophies. These conditions are characterized by progressive accumulation of protein deposits of different ultrastructure. Herein, we studied the corneas with mutations at kerato-epithelin residue Arg-124 resulting in amyloid (R124C), non-amyloid (R124L), and a mixed pattern of deposition (R124H). We found that aggregated kerato-epithelin comprised all types of pathological deposits. Each mutation was associated with characteristic changes of protein turnover in corneal tissue. Amyloidogenesis in R124C corneas was accompanied by the accumulation of N-terminal kerato-epithelin fragments, whereby species of 44 kDa were the major constituents of amyloid fibrils. R124H corneas with prevailing non-amyloid inclusions showed accumulation of a new 66-kDa species altogether with the full-size 68-kDa form. Finally, in R124L cornea with non amyloid deposits, we found only the accumulation of the 68-kDa form. Two-dimensional gels revealed mutation-specific changes in the processing of the full-size protein in all affected corneas. It appears that substitutions at the same residue (Arg-124) result in cornea-specific deposition of kerato-epithelin via distinct aggregation pathways each involving altered turnover of the protein in corneal tissue.
Amyloid, Animals, Chromosomes, Human, Pair 5, Cornea, Corneal Dystrophies, Hereditary, Extracellular Matrix Proteins, Humans, Molecular Weight, Mutation, Neoplasm Proteins, Rabbits, Transforming Growth Factor beta
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