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

J Biol Chem. 2000 Apr 14;275(15):11465-9. doi: 10.1074/jbc.275.15.11465.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid / metabolism*
  • Animals
  • Chromosomes, Human, Pair 5*
  • Cornea / chemistry
  • Corneal Dystrophies, Hereditary / genetics*
  • Extracellular Matrix Proteins*
  • Humans
  • Molecular Weight
  • Mutation*
  • Neoplasm Proteins / analysis
  • Neoplasm Proteins / genetics*
  • Neoplasm Proteins / metabolism
  • Rabbits
  • Transforming Growth Factor beta*


  • Amyloid
  • Extracellular Matrix Proteins
  • Neoplasm Proteins
  • Transforming Growth Factor beta
  • betaIG-H3 protein