Membrane IL-1: IL-1 alpha precursor binds to the plasma membrane via a lectin-like interaction.
Although biologically active IL-1 associated with plasma membrane has been demonstrated in both mouse and man, a biochemical mechanism for membrane anchoring has not been described. We have analyzed the nature of membrane IL-1 in stimulated murine macrophages. We show that it consists of an IL-1 alpha precursor bound to the plasma membrane via a lectin-like interaction that is specifically dissociated with D-mannose. The dissociated IL-1 was detected as both a biological activity and, by immunoprecipitation and SDS-PAGE, as a 33 kDa IL-1 alpha precursor. Treatment of macrophages with D-mannose before fixation depleted detectable IL-1 biological activity associated with the membrane. Pro-IL-1 alpha was glycosylated in these cells, as shown by incorporation of D-[14C]mannose; thus it is likely that a cell surface lectin binds pro-IL-1 via these carbohydrate residues. In addition to anchoring IL-1 precursor to the plasma membrane, this lectin-like interaction may also be important in the overall regulation of IL-1 release.
Brody
D T
DT
Program Resources, Inc., National Cancer Institute, Frederick, MD 21701.
Durum
S K
SK
D000818:Animals; D002250:Carbon Radioisotopes / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D006031:Glycosylation; D007375:Interleukin-1 / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D037102:Lectins / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D008358:Mannose / Q000494:pharmacology; D008565:Membrane Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008970:Molecular Weight; D011498:Protein Precursors / Q000096:biosynthesis / Q000378:metabolism*
D002250:Carbon Radioisotopes; D007375:Interleukin-1; D037102:Lectins; D008565:Membrane Proteins; D011498:Protein Precursors; D008358:Mannose