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Mortalin is a novel mediator of erythropoietin signaling
Author(s) -
Ohtsuka Rie,
Abe Yasunobu,
Fujii Tomomi,
Yamamoto Masahiro,
Nishimura Junji,
Takayanagi Ryoichi,
Muta Koichiro
Publication year - 2007
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/j.1600-0609.2007.00870.x
Subject(s) - erythropoietin , microbiology and biotechnology , progenitor cell , cell growth , biology , cancer research , stem cell , biochemistry , endocrinology
Erythropoietin (EPO) stimulates erythroid growth by enhancing the proliferation, maturation and survival of late‐stage erythroid progenitor cells. However, the entire process of EPO stimulation remains undetermined. To further clarify the intracellular mechanisms by which EPO affects the growth of erythroid progenitor cells, we analyzed proteins obtained from purified human erythroid colony‐forming cells (ECFCs) cultured with or without EPO, and one of the proteins apparently related with EPO stimuli was identified as mortalin (mthsp70/PBP74/Grp75/mot‐2), which is a member of the heat shock protein 70 family of chaperones. The amount of mortalin mRNA in ECFCs increased in an EPO dose‐dependent manner, and ECFC growth was dependent on the amount of mortalin. Furthermore, expression of mortalin in ECFCs was suppressed by a phosphatidylinositol 3‐kinase inhibitor. Finally, we analyzed gene expression patterns in ECFCs cultured with or without EPO after treatment with mortalin small interfering RNA (siRNA) using a DNA microarray. When ECFCs treated with mortalin siRNA were cultured with EPO, the expression of several genes overlapped with the profile seen in control ECFCs cultured without EPO. Our data suggest that mortalin is involved in the mediation of EPO signaling and plays an important role in stimulating the growth of erythroid progenitor cells.