A PHOTOACTIVATABLE PROBE FOR THE NA+/H+-EXCHANGER CROSS-LINKS A 66-KDA RENAL BRUSH-BORDER MEMBRANE-PROTEIN

  • 5 April 1990
    • journal article
    • research article
    • Vol. 265  (10) , 5341-5344
Abstract
Earlier studies on LIC-PK1 cells have demonstrated two pharmacologically distinct Na+/H+ exchangers in renal epithelia. In addition, the cDNA clone for the human Na+/H+ antiporter which is growth factor activatable has been isolated and expressed (Sardet, C., Franchi, A., and Pouyssegur, J. (1989) Cell 56, 271-280). We report here the synthesis of an amiloride analogue that can be photoactivated and labeled with 125I. This analogue covalently cross-links a 66-kDa protein of bovine renal brush border membranes. A rabbit polyclonal antibody that was directed against a 20-amino acid peptide of the cytoplasmic domain of its human Na+/H+ antiporter also gives a positive Western against 66-kDa protein of bovine brush border membranes. Thus, the photoactive probe may be helpful in the isolation and purification in the brush border Na+/H+ exchanger.