Lymphotoxin-induced loss of plasma-membrane protein.
Lymphotoxin-sensitive L cells were prelabeled with isotopically marked leucine and exposed either to human alpha-lymphotoxin (alpha-LT) or control buffer. Plasma membranes were then isolated from these cells, and TCA-precipitable leucine was determined as a measure of membrane protein. Human alpha-LT caused a marked reduction of plasmalemmal protein in LT-sensitive target cells. This loss of protein was general, not restricted to specific fractions, as assessed by sodium dodecyl sulfate (SDS)--polyacrylamide gel electrophoresis. Since purified alpha-LT had no detectable proteolytic activity, the effect of the lymphokine is not readily explained by direct enzymatic action on plasma-membrane protein. In contrast, there was no plasma--membrane protein loss in LT-resistant target cells on exposure to alpha-lymphotoxin.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D006868:Hydrolysis; D007739:L Cells; D008233:Lymphotoxin-alpha / Q000378:metabolism / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice
D008233:Lymphotoxin-alpha; D008565:Membrane Proteins