Identification of distinct receptors for two hemopoietic growth factors (granulocyte colony-stimulating factor and multipotential colony-stimulating factor) by chemical cross-linking.
Granulocyte colony-stimulating factor (G-CSF) and multipotential colony-stimulating factor (multi-CSF or interleukin 3) are two members of a family of hemopoietic growth and differentiation factors. Using biologically active radioiodinated derivatives and chemical cross-linking (predominantly with the homobifunctional reagent disuccinimidyl suberate) followed by gel electrophoresis and autoradiography, receptors for these two factors have been identified. The G-CSF receptor was identified as a single subunit protein of Mr approximately 150,000 while two molecular species able to specifically cross-link to 125I-multi-CSF were identified of Mr approximately 75,000 and 60,000. For both CSFs specificity of formation of cross-linked species was demonstrated by showing that the homologous unlabeled CSF (but not other CSFs) competed for formation of the complexes with the appropriate dose-response relation, by showing that saturation occurred over the appropriate range of 125I-CSF concentration and by showing that the cellular specificity of CSF binding paralleled that for cross-linked complex formation. The formation of cross-linked complexes was dependent on the concentration and type of chemical cross-linker, especially for cross-linking of 125I-multi-CSF. Based on a number of criteria it is suggested that the two species cross-linked to 125I-multi-CSF do not represent receptors of different affinity but, rather, two noncovalently associated subunits of a receptor complex.
D000818:Animals; D002460:Cell Line; D003115:Colony-Stimulating Factors / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D006098:Granulocytes / Q000166:cytology; D007377:Interleukin-3; D008222:Lymphokines / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D011956:Receptors, Cell Surface / Q000032:analysis*; D016184:Receptors, Colony-Stimulating Factor; D011971:Receptors, Immunologic / Q000032:analysis*; D016185:Receptors, Interleukin-3; D013388:Succinimides / Q000494:pharmacology
D003115:Colony-Stimulating Factors; D003432:Cross-Linking Reagents; D007377:Interleukin-3; D008222:Lymphokines; D011956:Receptors, Cell Surface; D016184:Receptors, Colony-Stimulating Factor; D011971:Receptors, Immunologic; D016185:Receptors, Interleukin-3; D013388:Succinimides; C019358:disuccinimidyl suberate