title: Tissue inhibitor of metalloproteinase-3 differentially binds to components of Bruch's membrane.
abstract: BACKGROUND
  Sorsby's fundus dystrophy (SFD) is caused by mutations in tissue inhibitor of metalloproteinase (TIMP)-3 and, with the exception of early onset, is similar to age-related macular degeneration. The pathological features of this condition relate to the accumulation of TIMP-3 in Bruch's membrane.
  
  
  OBJECTIVE
  To compare the extracellular membrane-binding characteristics of wild-type and four SFD-mutant TIMP-3s.
  
  
  METHODS
  COS-7 cells were transfected with wild-type, Ser-181, Gly-167, Ser-156 and Tyr-168 SFD-mutant TIMP-3 cDNA. The TIMP-3 proteins subsequently synthesised were harvested, analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, semiquantified by ELISA and used in binding assays on the basis of the retention of the wild-type and SFD-mutant TIMP-3 proteins by components of Bruch's membrane.
  
  
  RESULTS
  SFD-mutant TIMP-3s could not be distinguished from wild-type TIMP-3 by the extents to which they aggregated or adhered to type-I collagen, type-IV collagen, fibronectin, laminin, elastin, chondroitin sulphates A, B and C, and heparin sulphate. Of these macromolecules, the wild-type and SFD-mutant TIMP-3s exhibited greatest affinity for elastin and laminin.
  
  
  CONCLUSIONS
  The similarity in the physical and extracellular membrane-binding characteristics of wild-type and SFD-mutant TIMP-3s indicates that these properties are not responsible for the difference in timing of onset of SFD and age-related macular degeneration.
authors.affiliation: Academic Unit of Ophthalmology, University of Bristol, Bristol Eye Hospital, Bristol, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Majid
authors.forename: V A
authors.initials: VA
authors.lastname: Smith
authors.forename: F J
authors.initials: FJ
authors.lastname: Matthews
authors.forename: A C
authors.initials: AC
authors.lastname: Newby
authors.forename: A D
authors.initials: AD
authors.lastname: Dick
mesh_terms: D000818:Animals; D016570:Bruch Membrane / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D003317:Corneal Dystrophies, Hereditary / Q000235:genetics; D004549:Elastin / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D007797:Laminin / Q000378:metabolism; D017354:Point Mutation; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: D007797:Laminin; D019717:Tissue Inhibitor of Metalloproteinase-3; D004549:Elastin