A growth signal with an artificially induced erythropoietin receptor-gp130cytoplasmic domain heterodimer

We report a strategy for generating efficient signal transduction with unna tural heterologous receptor combinations. As previously described [Ueda, H. , Kawahara, M. et al (2000) J. Immunol Methods 241, 159-170], chimeric rece ptors composed of the V-H/V-L domains of anti-hen egg lysozyme antibody HyH EL-10 and N-terminally truncated erythropoietin receptor (EpoR) can be acti vated by lysozyme. When the cytoplasmic domains of these receptors were sub stituted with one derived from gp130, IL-3 dependent Ba/F3 cells expressing both V-H-gP130 and V-L-gpl30 grew dose-dependently when given lysozyme wit hout IL-3. However, cells expressing the heterologous pair of V-H-gpl30 and V-L-EpoR also showed more efficient and stricter lysozyme-dependent prolif eration in the absence of IL-3, indicating this combination is as an effici ent and strict signal transducer as wild-type EpoR. The immunoprecipitation data indicated the existence of a preformed V-H-gpl30 and V-L-EpoR heterod imer in the absence of lysozyme, suggesting the crucial role of a receptor conformational change in signal triggering as well as wildtype EpoR and gp1 30. Phosphorylation of JAK2, STAT3, and STAT5 was observed upon the additio n of lysozyme, suggesting the activation of both EpoR- and gp130-derived si gnals.