@article{MuellerDieckmannSebaldetal.1994, author = {M{\"u}ller, T. and Dieckmann, T. and Sebald, Walter and Oschkinat, H.}, title = {Aspects of receptor binding and signalling of interleukin-4 investigated by site-directed mutagenesis and NMR spectroscopy}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62444}, year = {1994}, abstract = {Cytokines are hormones that carry information from ceJI to ceH. This information is read from their surface upon binding to transmembrane receptors and by the subsequent initiation of receptor oligomerization. An inftuence on this process through mutagenesis on the hormone surface is highly desirab)e for medical reasons. However, an understanding of hormone-receptor interactions requires insight into the structural changes introduced by the mutations. In this line structural studies on human TL-4 and the medically important IL-4 antagonists YI24D and Y124G are presented. The site a.round YI24 is an important epitope responsible for the a.bility of 11-4 t.o ca.use a signal in the target cells. It is shown that the local main-chain structure around residue 124 in the variants remains unchanged. A strategy is presented here which allows the study of these types of proteins and their variants by NMR which does not require carbon Iabeiied sa.mples.}, subject = {Biochemie}, language = {en} } @article{LehrnbecherPootOrschescheketal.1994, author = {Lehrnbecher, T. and Poot, M. and Orscheschek, K. and Sebald, Walter and Feller, A. C. and Merz, H.}, title = {Interleukin 7 as interleukin 9 drives phytohemagglutinin-activated T cells through several cell cycles; no synergism between interleukin 7, interleukin 9 and interleukin 4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62438}, year = {1994}, abstract = {The effects of the interlenkins IL-7 and IL-9 on cell cycle progression were investigated by conventional [3H]thymidine incorporation and by the bivariate BrdU/Hoechst technique. 8oth IL· 7 and IL-9 drive phytohemagglutinin-activated T cells through more than one cell cycle, but IL-7 wasmorepotent on cell cycle progression than IL-9. Neither synergistic nor inhibitory effects were seen between various combinations of the lymphokines IL-7, IL-9 and IL-4 compared to each lymphokine alone. When T cells are activated with phytohemagglutinin for 3 days, all or most IL-4 responsive cells respond to IL-7 as weil, whereas only a part of IL-7 responders are IL-4 responders. In contrast, when T cells are activated with phytohemagglutinin for 7 days, the quantitative data of the cell cycle distribution soggest that the population of IL-7 responders is at least an overlapping, if not a real subset of the population of the IL-4 responders.}, subject = {Biochemie}, language = {en} } @article{DemchukMuellerOschkinatetal.1994, author = {Demchuk, E. and Mueller, T. and Oschkinat, H. and Sebald, Walter and Wade, R. C.}, title = {Receptor binding properties of four-helix-bundle growth factors deduced from electrostatic analysis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62424}, year = {1994}, abstract = {Hormones of the hematopoietin class mediate signal transduction by binding to specific transmembrane receptors. Structural data show that the human growth hormone (hGH) forms a complex with a homodimeric receptor and that hGH is a member of a class of hematopoietins possessing an antiparallel 4-a-helix bundle fold. Mutagenesis experiments suggest that electrostatic interactions may have an important influence on hormonereceptor recognition. In order to examine the specificity of hormone-receptor complexation, an analysis was made of the electrostatic potentials of hGH, interleukin-2 (IL-2), interleukin-4 (IL-4), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and the hGH and IL-4 receptors. The binding surfaces of hGH and its receptor, and of IL-4 and its receptor, show complementary electrostatic potentials. The potentials of the hGH and its receptor display approximately 2-fold rotational symmetry because the receptor subunits are identical. In contrast, the potentials of GM-CSF and IL-2 Iack such symmetry, consistent with their known high affinity for hetero-oligomeric receptors. Analysis of the electrostatic potentials supports a recently proposed hetero-oligomeric model for a high-affinity IL-4 receptor and suggests a possible new receptor binding mode for G-CSF; it also provides valuable information for guiding structural and mutagenesis studies of signal-transducing proteins and their receptors.}, subject = {Biochemie}, language = {en} } @article{ReuschArnoldHeusseretal.1994, author = {Reusch, P. and Arnold, S. and Heusser, C. and Wagner, K. and Weston, B. and Sebald, Walter}, title = {Neutralizing monoclonal antibodies define two different functional sites in human interleukin-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62418}, year = {1994}, abstract = {Human interleukin-4 (IL-4) is a small four-helix-bundle protein which is essential for organizing defense reactions against macroparasites, in particular helminths. Human IL-4 also appears to exert a pathophysiological role during various IgE-mediated allergic diseases. Seven different monoclonal antibodies neutralizing the activity of human IL-4 were studied in order to identify functionally important epitopes. A collection of 41 purified IL-4 variants was used to analyse how defined amino acid replacements affect binding affinity for each individual mAb. Specific amino acid positions could be assigned to four different epitopes. mAbs recognizing epitopes on helix A and/or C interfered with IL-4 receptor binding and thus inhibited IL-4 function. However, other mAbs also inhibiting IL-4 function recognized an epitope on helix D of IL-4 and did not inhibit IL-4 binding to the receptor protein. One mAb, recognizing N-terminal and C-terminal residues, partially competed for binding to the receptor. The results of these mAb epitope analyses confirm and extend previous data on the functional consequences of the amino acid replacements which showed that amino acid residues in helices A and C of IL-4 provide a binding site for the cloned IL-4 receptor and that a signalling site in helix D interacts with a further receptor protein.}, subject = {Biochemie}, language = {en} } @article{MuellerSebaldOschkinat1994, author = {M{\"u}ller, T. and Sebald, Walter and Oschkinat, H.}, title = {Antagonist design through forced electrostatic mismatch}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62408}, year = {1994}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{TonyShenReuschetal.1994, author = {Tony, H. P. and Shen, B. J. and Reusch, P. and Sebald, Walter}, title = {Design of human interleukin-4 antagonists inhibiting interleukin-4-dependent and interleukin-13-dependent responses in T-cells and B-cells with high efficiency}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62394}, year = {1994}, abstract = {Human interleukin-4 possesses two distinct sites for receptor activation. A signaHing site, comprising residues near the C-terminus on helix D, determines the efficacy of interleukin-4 signal transduction without affecting the binding to the interleukin-4 receptor a subunit. A complete antagonist and a series of low-efficacy agonist variants of human interleukin-4 could be generated by introducing combinations of two or three negatively charged aspartic acid residues in this site at positions 121, 124, and 125. One of the double variants, designated [R121D,Y124D]interleukin-4, with replacements of b{\"o}th Arg121 and Tyr124 by aspartic acid residues was completely inactive in all analysed cellular responses. The loss of efficacy in [R121D,Y124D]interleukin-4 is estimated to be larger than 2000-fold. Variant [R121D,Y124D]interleukin-4 was also a perfect antagonist for inhibition of interleukin-13-dependent responses in B-cells and the TF-1 cellline with a K\(_i\) value of approximately 100 pM. In addition, inhibition of both interleukin-4-induced and interleuk.in-13- induced responses could be obtained by monoclonal antibody X2/45 raised against interleukin-4Rm the extracellular domain of the interleuk.in-4 receptor a subunit. These results indicate that efficient interleukin-4 antagonists can be designed on the basis of a sequential two-step activation model. In addition, the experiments indicate the functional participation of the interleukin-4 receptor a subunit in the interleukin-13 receptor system.}, subject = {Biochemie}, language = {en} } @article{KueblerReutherKirchneretal.1994, author = {K{\"u}bler, N. and Reuther, J. and Kirchner, T. and Pfaff, M. and M{\"u}ller-Hermelink, H. K. and Albert, R. and Sebald, Walter}, title = {IgG monoclonal antibodies that inhibit osteoinductivity of human bone matrix-derived proteins (hBMP/NCP)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62388}, year = {1994}, abstract = {Monoclonal hBMP/NCP (human bone morphogenetic protein anrl associaterl noncollagenous proteins) antiborlies of the lgG class were prorlucerl. In vitro, 12 of 19 hBMP/NCP antiborlies showerl functional inhibition of hBMP/ NCP-induced chondroneogenesis in a neonatal muscle tissue assay. Inducing factors were characterized by their inhibiting antibodies with immunoblotting. Several peptide factors seem to be involved in the cascade of inducerl chondro- and osteogenesis.}, subject = {Biochemie}, language = {en} } @article{SchwarzHameisterGessleretal.1994, author = {Schwarz, Klaus and Hameister, Horst and Gessler, Manfred and Grzeschik, Karl-Heinz and Hansen-Hagge, Thomas E. and Bartram, Claus R.}, title = {Confirmation of the localization of the human recombination activating gene 1 (RAG1) to chromosome 11p13}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59136}, year = {1994}, abstract = {The human recombination activating gene 1 (RAGl) has previously been mapped to chromosomes 14q and 11 p. Here we confirm the chromosome 11 assignment by two independent approaches: autoradiographic and fluorescence in situ hybridization to metaphase spreads and analysis of human-hamster somatic cell hybrid DNA by the polymerase chain reaction (PCR) and Southern blotting. Our results unequivocally localize RAG1 to llp13.}, subject = {Biochemie}, language = {en} } @article{SchwartzNeveEisenmanetal.1994, author = {Schwartz, Faina and Neve, Rachel and Eisenman, Robert and Gessler, Manfred and Bruns, Gail}, title = {A WAGR region gene between PAX-6 and FSHB expressed in fetal brain}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59125}, year = {1994}, abstract = {Developmental delay or mental retardation is a frequent component of multi-system anomaly syndromes associated with chromosomal deletions. Isolation of genes involved in the mental dysfunction in these disorders should define loci important in brain formation or function. We have identified a highly conserved locus in the distal part of 11 p 13 that is prominently expressed in fetal brain. Minimal expression is observed in a number of other fetal tissues. The gene maps distal to PAX-6 but proximal to the loci for brain-derived neurotrophic factor (BDNF) and the beta subunit of follicle stimulating hormone (FSHB), within a region previously implicated in the mental retardation component of some WAGR syndrome patients. Within fetal brain, the corresponding transcript is prominent in frontal, motor and primary visual cortex as weil as in the caudate-putamen. The characteristics of this gene, including the striking evolutionary conservation at the locus, suggest that the encoded protein may function in brain development.}, subject = {Biochemie}, language = {en} }