Limited proteolysis as a probe for arrested conformational maturation of delta F508 CFTR

Nat Struct Biol. 1998 Mar;5(3):180-3. doi: 10.1038/nsb0398-180.


Deletion of phenylalanine 508 (delta F508) in the cystic fibrosis transmembrane-conductance regulator (CFTR) prevents the otherwise functional protein from reaching the plasma membrane and is the leading cause of cystic fibrosis. Indirect evidence suggests that the mutant protein, delta F508 CFTR, is misfolded. We address this issue directly, using comparative limited proteolysis of CFTR at steady steady state and during biosynthesis in the native microsomal environment. Distinct protease susceptibilities suggest that cytosolic domain conformations of wild type and delta F508 CFTR differ, not only near F508, but globally. Moreover, delta F508 CFTR proteolytic cleavage patterns were indistinguishable from those of the early folding intermediate of wild type CFTR. The results suggest that the delta F508 mutation causes the accumulation of a form of the protein that resembles an intermediate in the biogenesis of the wild type CFTR, rather than induces the production of non-native variant.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • CHO Cells
  • Cricetinae
  • Cystic Fibrosis / genetics
  • Cystic Fibrosis / metabolism
  • Cystic Fibrosis Transmembrane Conductance Regulator / chemistry*
  • Cystic Fibrosis Transmembrane Conductance Regulator / isolation & purification
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
  • Endopeptidases / metabolism*
  • Humans
  • Microsomes / metabolism
  • Peptide Mapping
  • Phenylalanine
  • Protein Conformation*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Sequence Deletion
  • Transfection


  • CFTR protein, human
  • Recombinant Proteins
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Phenylalanine
  • Endopeptidases