Characterization of interleukin-11 receptor and protein tyrosine phosphorylation induced by interleukin-11 in mouse 3T3-L1 cells.
In this study, we have characterized the biochemical nature of interleukin (IL)-11 receptors (IL-11R) and determined the possible signal transduction pathways mediated by IL-11 in 3T3-L1 mouse preadipocytes. The results show that IL-11 strongly inhibited lipoprotein lipase activity and adipogenesis in 3T3-L1 cells, and the suppression of lipoprotein lipase activity by IL-11 was controlled at the post-transcriptional level. The ability of IL-11 to inhibit lipoprotein lipase activity and adipogenesis therefore reflected the expression of functional IL-11R on the cell surface. Scatchard plot analysis according to specific binding data revealed the existence of a single class of high affinity IL-11R with a Kd of 3.49 x 10(-10) M and a receptor density of 5140 sites/cell on 3T3-L1 cells. Affinity cross-linking studies with 125I-IL-11 indicated that IL-11R consists of a single polypeptide chain of 151 kDa in size. Furthermore, we have studied the role of protein tyrosine phosphorylation in the IL-11R-linked signal transduction pathways. The results show that IL-11R ligation rapidly and transiently stimulated tyrosine phosphorylation of 152-, 94-, 47-, and 44-kDa proteins. This effect is specific for IL-11 since neutralizing antibody to IL-11 abrogated IL-11-induced tyrosine phosphorylation, and other cytokines such as IL-6 and IL-1 alpha did not change the tyrosine phosphorylation pattern in 3T3-L1 cells. These results suggest that IL-11R is closely linked to a functional protein-tyrosine kinase pathway, and tyrosine phosphorylation may be a key step in the initiation of the IL-11R-mediated transmembrane signaling.
Yin
T
T
Department of Medicine, Indiana University School of Medicine, Indianapolis 46202.
Miyazawa
K
K
Yang
Y C
YC
D016475:3T3 Cells; D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D015152:Blotting, Northern; D015153:Blotting, Western; D003432:Cross-Linking Reagents; D017370:Interleukin-11; D053703:Interleukin-11 Receptor alpha Subunit; D007378:Interleukins / Q000494:pharmacology*; D008071:Lipoprotein Lipase / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational; D012313:RNA / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism*; D018123:Receptors, Interleukin; D053702:Receptors, Interleukin-11; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism*
D003432:Cross-Linking Reagents; C508429:Il11ra1 protein, mouse; C508431:Il11ra2 protein, mouse; D017370:Interleukin-11; D053703:Interleukin-11 Receptor alpha Subunit; D007378:Interleukins; D011971:Receptors, Immunologic; D018123:Receptors, Interleukin; D053702:Receptors, Interleukin-11; D014443:Tyrosine; D012313:RNA; D008071:Lipoprotein Lipase