Hypothetical roles of TEF and E2A-HLF. TEF down-regulates the expression of the common β (β_C) chain and inactivates IL-3 signaling pathways, which are critical for both cell proliferation and cell survival. In addition, TEF promotes cell survival in the absence of survival signalings downstream of IL-3. Consequently, cells in the G₀/G₁ phase accumulated without undergoing apoptosis. In contrast, E2A-HLF blocks apoptosis without regulating the expression of cytokine receptors.