Binding and internalization of the 163-171 fragment of human IL-1 beta.
The mechanisms of cell association of the human interleukin (IL-1 beta) immunostimulatory fragment 163-171 have been studied. The fragment was able to associate abundantly to both IL-1R- and IL-1R+ cells. Binding was strictly temperature dependent, was not saturable and could be inhibited by excess amounts of unlabelled 163-171 peptide but not by IL-1 beta, suggesting that the 163-171 fragment is not an IL-1R-binding domain of IL-1 beta. The fragment is readily internalized by cells by a cytochalasin-insensitive mechanism and it localizes mainly in the cytoplasm. It is concluded that the active domain 163-171 of IL-1 beta can be taken up by cells through a receptor-independent, temperature-dependent mechanisms and that its ability to activate cellular functions is based on IL-1R-independent intracellular pathways.
Boraschi
D
D
Sclavo Research Center, Siena, Italy.
Ghiara
P
P
Scapigliati
G
G
Villa
L
L
Sette
A
A
Tagliabue
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D003593:Cytoplasm; D004058:Diffusion; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism* / Q000494:pharmacology; D053583:Interleukin-1beta; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D011971:Receptors, Immunologic / Q000378:metabolism; D017472:Receptors, Interleukin-1; D015398:Signal Transduction; D013696:Temperature; D014407:Tumor Cells, Cultured / Q000378:metabolism
D007375:Interleukin-1; D053583:Interleukin-1beta; D010446:Peptide Fragments; D011971:Receptors, Immunologic; D017472:Receptors, Interleukin-1; C052994:interleukin-1beta (163-171)