Inhibition of cap formation on lymphocytes by free fatty acids is not mediated by a depletion of ATP.
We have previously reported that cis-unsaturated free fatty acids, e.g. linoleic acid, introduced as free fatty acids into lymphocyte membranes inhibited surface immunoglobulin capping. Trans-unsaturated and saturated free fatty acids had no effect. These results were interpreted as being due to perturbation of specific membrane lipid domains. Corps, A. N., Pozzan, T., Hesketh, T. R., and Metcalfe, J. C. (1980) J. Biol. Chem. 255, 10566-10568) in a recent paper argued, however, that linoleic acid causes depletion of ATP, as measured by the luciferin/luciferase assay, and respiratory uncoupling. We now present data showing that under the same conditions as the capping inhibition, there is neither ATP depletion, as found using a hexokinase/glucose-6-phosphate dehydrogenase assay, nor respiratory uncoupling. Linoleic acid produces artifacts in ATP measurements made using the luciferin/luciferase assay which leads to an erroneous conclusion regarding the ATP dependence of the capping inhibition.
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D005230:Fatty Acids, Nonesterified / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D008214:Lymphocytes / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D010101:Oxygen Consumption / Q000187:drug effects
D005230:Fatty Acids, Nonesterified; D000255:Adenosine Triphosphate