Rosenau W, Burke GC, Moy J. Lymphotoxin-induced loss of plasma-membrane protein.
THE AMERICAN JOURNAL OF PATHOLOGY 1979;
94:473-82. [PMID:
311590 PMCID:
PMC2042268]
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Abstract
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.
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