Production and secretion of interleukin 1 receptor antagonist in monocytes and keratinocytes.
IL-1 receptor antagonist (IL-1ra) is a newly described member of the IL-1 family, isolated from supernatants of Ig stimulated monocytes, that binds competitively to IL-1 receptors without stimulating target cells. Also epithelial cells produce IL-1ra in a form which lacks a secretory signal sequence. Here we have compared the biosynthesis and secretion of IL-1ra in monocytes and keratinocytes. Our data show that monocytes produce two molecular forms of IL-1ra, of 18 Kd and 23 Kd respectively, which differ in the degree of glycosylation. Both forms are secreted via the "classical" endoplasmic reticulum (ER)-Golgi secretory pathway. By contrast keratinocytes produce IL-1ra in a molecular form of 20 Kd, which is not N-glycosylated: 20 Kd IL-1ra is detectable in supernatants of keratinocytes, although in small amounts. The presence of IL-1ra in keratinocytes cultures fluids is not inhibited by Brefeldin A (BFA), suggesting a possible secretion through the leaderless secretory pathway.
Corradi
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A
Istituto Nazionale per la Ricerca sul Cancro, Genova.
Bajetto
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A
Cozzolino
F
F
Rubartelli
A
A
D001709:Biotechnology; D002478:Cells, Cultured; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000096:biosynthesis; D015603:Keratinocytes / Q000378:metabolism*; D008970:Molecular Weight; D009000:Monocytes / Q000378:metabolism*; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors*; D012795:Sialoglycoproteins / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism
C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D017472:Receptors, Interleukin-1; D012795:Sialoglycoproteins