The incorporation of radioactive phosphorus in the leucocyte during the extrusion of protein induced by staphylococcal leucocidin.

Abstract

Incubation with leukocidin stimulates the incorporation of P/sup 32/ into the adenosine tri- and di-phosphate and guanosine tri- and di-phosphate of the leukocyte. Incubation with leukocidin does not increase the permeability of the leukocyte to orthophosphate and in the presence of P/sup 32/ does not increase the radioactivity of the intracellular orthophosphate. In the presence of fluoride, iodoacetate, or arsenate the incorporation of P/sup 32/ into the lipids and nucleotides of the leukocidin-treated leukocyte is partially inhibited. The extrusion of BETA -glucuronidase is not affected under these conditions. Omission of calcium from the medium stimulates the incorporation of P/sup 32/ into the lipids of the leukocidin-treated leukocyte and reduces the amount of incorporation into the nucleotides. Either component of leukocidin adsorbed on the leukocyte can be neutralized by antibody. Addition of antibody to the leukocidin-treated leukocyte does not inhibit the incorporation of P/sup 32/ into the nucleotides. Treatment with leukocidin decreases the rate of loss of radioactivity from the nucleotides of leukocytes labeled with P/sup 32/ and suspended in a medium of low specific radioactivity. Treatment with leukocidin reduces the amount of STAC/sup 14/!adenine incorporated into adenosine triphosphate and the amount of STAC/sup 14/!acetate incorporated into the lipids of themore » cell. It is suggested that the stimulation of incorporation of P/sup 32/ in the leukocidin-treated leukocyte does not result from- an increased rate of turnover of any phosphorus compound of the cell but can result from direct utilization at the cell surface of the external orthophosphate. (auth)« less