Dw. Haas et al., LIPOPOLYSACCHARIDE STIMULATES PHOSPHORYLATION OF EUKARYOTIC INITIATION FACTOR-4F IN MACROPHAGES AND TUMOR-NECROSIS-FACTOR PARTICIPATES IN THIS EVENT, Second messengers and phosphoproteins, 14(3), 1993, pp. 163-171
Bacterial lipopolysaccharide (LPS) produces rapid changes in macrophag
e protein synthesis and function. Phosphorylation of the 25 kDa mRNA c
ap-binding protein (eIF-4E) in model systems regulates the efficiency
of protein synthesis. We report that both LPS and tumor necrosis facto
r-alpha (TNF-alpha) stimulate phosphorylation of eIF-4E and the p220 c
omponent of eIF-4F in bone marrow-derived macrophages. Moreover, anti-
TNF-alpha antibodies inhibit LPS-stimulated phosphorylation of eIF-4E
and p220 by 43% (+/- 6%) and 50% (+/- 5%), respectively. Our results i
ndicate that LPS stimulates eIF-4F phosphorylation by a TNF-alpha-depe
ndent mechanism, and suggest that phosphorylation of eIF-4F might play
a role in the post-transcriptional regulation of gene expression in m
acrophages exposed to LPS.