Communications
STAT5 Activation Correlates with Erythropoietin Receptor-mediated Erythroid Differentiation of an Erythroleukemia Cell Line*

https://doi.org/10.1074/jbc.272.13.8149Get rights and content
Under a Creative Commons license
open access

Interaction between erythropoietin (EPO) and its membrane receptor induces the proliferation and differentiation of erythroid progenitors. EPO has been shown to activate the JAK2-STAT5 pathway in various hematopoietic cell lines, although the physiological role of this pathway is unclear. We have previously shown that epidermal growth factor activates a chimeric receptor bearing the extracellular domain of the epidermal growth factor receptor linked to the cytoplasmic domain of the EPO receptor, resulting in proliferation of interleukin-3-dependent hematopoietic cells and erythroid differentiation (globin synthesis) of EPO-responsive erythroleukemia cells. In the present study, we introduced various deletion and tyrosine to phenylalanine substitution in the cytoplasmic domain of the chimeric receptor and expressed these mutant chimeras in an EPO-responsive erythroleukemia cell line, ELM-I-1. Mutant chimeric receptors retaining either Tyr343 or Tyr401 could activate STAT5, judged by tyrosine-phosphorylation of STAT5 and induction of CIS, a target gene of STAT5. These mutants were able to induce erythroid differentiation. However, a chimeric receptor containing both Y343F and Y401F mutations could not activate STAT5 nor induce erythroid differentiation. Thus, Tyr343 or Tyr401 of the EPO receptor are independently necessary for erythroid differentiation as well as STAT5 activation. Moreover, exogenous expression of dominant-negative STAT5 suppressed EPO-dependent erythroid differentiation. These findings suggest that STAT5 plays an important role in erythroid differentiation through the EPO receptor cytoplasmic domain.

Cited by (0)

*

This work was supported in part by grants from the Ministry of Science, Education and Culture of Japan, the Kato Memorial Foundation, the Japanese Foundation for Multidisciplinary Treatment of Cancer, the Haraguchi Memorial Foundation, the Uehara Memorial Foundation, the Kowa Life Science Foundation, and the Naito Memorial Foundation. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

1

The abbreviations used are:

    EPO

    erythropoietin

    EPOR

    erythropoietin receptor

    IL

    interleukin

    EGF

    epidermal growth factor

    EGFR

    epidermal growth factor receptor

    wt

    wild type

    PCR

    polymerase chain reaction

    dn

    dominant-negative

    DMEM

    Dulbecco's modified Eagle's medium.