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Processing of newly synthesized cachectin/tumor necrosis factor in endotoxin-stimulate macrophages

Journal Article · · Biochemistry; (USA)
DOI:https://doi.org/10.1021/bi00488a025· OSTI ID:5922579
The biosynthesis and processing of cachetin/tumor necrosis factor (TNF) were examined in the murine macrophage-like cell line RAW 264.7. Lipipolysaccharide-stimulated cells secreted both glycosylated and nonglycosylated 17-kilodalton (kDa) mature cachectin/TNF into the culture medium. Secreted cachectin/TNF was derived from membrane-associated precursors that were precipitated by polyclonal antisera raised against either the mature protein or synthetic peptide fragments of the 79 amino acid cachectin/TNF prohormone sequence. About half of the precursors were N-glycosylated, apparently cotranslationally. The cachectin/TNF precursors were then proteolytically cleaved to release soluble mature cytokine into the medium, while the membrane-bound 14-kDa prosequence remained cell associated. During the period of LPS stimulation, the amount of macrophage cell surface cachectin/TNF remained at a low level, suggesting that both nonglycosylated and glycosylated precursors of cachectin/TNF are efficiently cleaved by these cells. These findings suggest the presence of a unique mechanism for the secretion of cachectin/TNF.
OSTI ID:
5922579
Journal Information:
Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:36; ISSN 0006-2960; ISSN BICHA
Country of Publication:
United States
Language:
English