A Growth Signal with an Artificially Induced Erythropoietin Receptor-gpl30 Cytoplasmic Domain Heterodimer1.

We report a strategy for generating efficient signal transduction with unnatural heterol-ogous receptor combinations. As previously described [Ueda, H., Kawahara, M. et aL (2000) J. Immunol. Methods 241, 159-170], chimeric receptors composed of the VR/VL domains of anti-hen egg lysozyme antibody HyHEL-10 and N-tenninally truncated erythropoietin receptor (EpoR) can be activated by lysozyme. When the cytoplasmic domains of these receptors were substituted with one derived from gpl30, IL-3 dependent Ba/F3 cells expressing both VH-gpl30 and VL-gpl30 grew dose-dependently when given lysozyme without IL-3. However, cells expressing the heterologous pair of VH-gpl30 and VL-EpoR also showed more efficient and stricter lysozyme-dependent proliferation in the absence of IL-3, indicating this combination is as an efficient and strict signal transducer as wild-type EpoR. The immunoprecipitation data indicated the existence of a preformed VH-gpl30 and VL-EpoR heterodimer in the absence of lysozyme, suggesting the crucial role of a receptor conformational change in signal triggering as well as wild-type EpoR and gpl30. Phosphorylation of JAK2, STAT3, and STAT5 was observed upon the addition of lysozyme, suggesting the activation of both EpoR- and gpl30-derived signals. [ABSTRACT FROM AUTHOR]