Acylation of cell-associated IL-1 by palmitic acid.
To determine whether membrane-associated IL-1 is palmitylated, we labeled LPS-activated human monocytes with [3H]palmitic acid. The plasma membranes were isolated, and the membrane proteins extracted and analyzed simultaneously by SDS-PAGE-autoradiography and Western blot analysis from the same gel. When the monocytes were labeled with [3H]palmitate, 23- and 31-kDa bands were visualized, for membrane-associated IL-1 and its precursor, respectively. The 31- and 23-kDa bands were excised from several gels and rehydrated and analyzed again by SDS-PAGE, autoradiography, and Western blot analysis. The 23- and 31-kDa bands appeared again by both methods. To further investigate membrane-associated IL-1 acylation, human monocytes were labeled with [3H]palmitate, the plasma membranes isolated, and the membrane proteins extracted by CHAPS detergent. Immunoprecipitation of isolated membrane proteins using anti-IL-1 antibodies revealed two bands of 23 and 31 kDa after autoradiography. The studies demonstrate that both membrane-associated IL-1 and the IL-1 precursor are acylated with palmitic acid.
Bakouche
O
O
Department of Cell Biology, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Moreau
J L
JL
Lachman
L B
LB
D000215:Acylation; D001345:Autoradiography; D015153:Blotting, Western; D002478:Cells, Cultured; D006031:Glycosylation; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism*; D008565:Membrane Proteins / Q000276:immunology; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism*; D011233:Precipitin Tests
D007376:Interleukin-2; D008565:Membrane Proteins; D010169:Palmitic Acids; D019308:Palmitic Acid