Effects of ammonia on human neutrophil N-formyl chemotactic peptide receptor-ligand interaction and cytoskeletal association.
Ammonia is a bacterial metabolite which is commonly used to alter cytoplasmic and lysosomal pH of eukaryotic cells. Here we examine its effect on external N-formyl peptide receptors of human neutrophils. Ammonia does not affect the number of N-formyl peptide receptors on the cell surface, nor the association of the ligand-receptor complex with the cytoskeleton. However, ammonia causes a marked decrease in the affinity of the chemotactic peptide receptor for its ligand. The Kd of untreated cell for the chemotactic peptide was 0.65 +/- 0.06 nM, whereas that of ammonia treated cells was 1.02 +/- 0.10 nM (Mean +/- SEM, N = 6). These results suggest that ammonia can affect external as well as internal cellular components. Since ammonia is used to alter lysosomal and cytoplasmic pH, and is a metabolite of common bacterial pathogens, these results bear directly on its use in cell biology and on its potential as a virulence factor.
Coppi
M
M
Department of Cell Biology, Forsyth Dental Research Center, Boston, MA 02115.
Niederman
R
R
D000595:Amino Acid Sequence; D000641:Ammonia / Q000494:pharmacology*; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D005452:Fluoresceins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008969:Molecular Sequence Data; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000378:metabolism*
D005452:Fluoresceins; D008024:Ligands; D009842:Oligopeptides; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; C061989:F-chemotactic peptide-fluorescein; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000641:Ammonia