Human EPOR Stable Cell Line - Ba/F3

Cell surface receptors receive signals from outside the cell and play a crucial role in regulating various aspects of cell behavior by coordinating the cellular response. Researchers have explored the role of the human erythropoietin receptor (EPOR) in cell proliferation by using a 46-residue artificial transmembrane protein aptamer, ELI-3. The key role of EPOR in erythropoiesis and other cellular processes is achieved through the formation of EPOR homodimers or hetero-oligomers of EPOR with other receptors. However, the mechanisms of heteroreceptor assembly and signaling are unclear. The researchers found that ELI-3 was able to bind and activate EPOR, thereby triggering growth factor independence in EPOR-expressing mouse BaF3 cells. The activity of ELI-3 was dependent on the transmembrane region of EPOR and the JAK2-binding site, rather than cytoplasmic tyrosine, which is used for signaling through conventional EPOR. In contrast, ELI-3-induced proliferation and activation of JAK/STAT signaling required the transmembrane and cytoplasmic domains of the cytokine receptor β-common subunit (βcR). Furthermore, ELI-3 could not induce erythroid differentiation of human primary hematopoietic progenitors but inhibited serum withdrawal-induced nonhematopoietic cell death.

Figure 1. Researchers used YX4 expression libraries to screen for novel traptamers synergizing EPOR in BaF3/hEPOR cells. BaF3/hEPOR cells normally require IL-3 for proliferation, but EPO or proteins that activate hEPOR can substitute for EPO. Following the screen, these cells survived in media lacking growth factors, indicating that these traptamers make the cell's growth factor independent. (He L, et al., 2019)