Erythropoietin-induced phosphorylation/degradation of BIM contributes to survival of erythroid cells.
Erythropoietin-induced phosphorylation/degradation of BIM contributes to survival of erythroid cells.
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DOI：
10.1016/j.exphem.2008.10.008
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发表时间：
2009-02
影响因子：
2.6
通讯作者：
Harada, Hisashi
中科院分区：
文献类型：
--
作者：
Abutin, Randolph M.;Chen, Jingchun;Lung, Tina K.;Lloyd, Joyce A.;Sawyer, Stephen T.;Harada, Hisashi
促凋亡蛋白BH3-Only BIM(BCL-2细胞死亡相互作用介体)可以将细胞因子受体信号转导与造血细胞的凋亡机制联系起来。在这里，我们研究了BIM在促红细胞生成素(EPO)介导的红系细胞存活中的作用。我们用shRNA下调了EPO依赖的HCD57红系细胞中BIM的表达，并用实时定量聚合酶链式反应、Western blots和流式细胞术检测了BIM的表达和细胞凋亡。对Bim缺陷(Bim−/−)小鼠进行血液学分析。BIM在原代小鼠红系细胞和不含EPO的HCD57细胞中表达增加。停用EPO后，Bim mRNA增加不到2倍，BIM蛋白增加10倍以上，提示BIM具有转录后调控作用。EPO处理导致BIM在丝氨酸65处迅速磷酸化，并且磷酸化与BIM的降解相关。MEK/ERK抑制剂U0126抑制ERK(细胞外信号调节激酶)，阻断BIM的磷酸化和降解，导致细胞凋亡。蛋白酶体抑制剂MG-132的处理也阻止了磷酸化BIM的降解。用shRNA下调BIM导致HCD57细胞对EPO停用或ERK抑制诱导的凋亡更具抵抗力。虽然我们观察到Bim−/−小鼠循环中的红细胞和网织红细胞数量没有明显变化，但Bim−/−小鼠的骨髓红系祖细胞数量减少，并且对U0126MEK/ERK抑制剂诱导的细胞凋亡具有更强的抵抗力。EPO部分通过ERK介导的磷酸化和BIM的蛋白酶体降解来保护红系细胞免于凋亡。
A pro-apoptotic BH3-only protein BIM (BCL-2 interacting mediator of cell death) can link cytokine receptor signaling with the apoptotic machinery in hematopoietic cells. We investigated here the role of BIM in erythropoietin (Epo)-mediated survival in erythroid cells. We down-regulated BIM in Epo-dependent HCD57 erythroid cells with shRNA, and used Real-time PCR, Western blots, and flow cytometry to characterize BIM expression and apoptosis. Hematologic analyses of BIM-deficient (Bim−/−) mice were conducted. BIM expression increases in primary murine erythroid cells and HCD57 cells deprived of Epo. Whereas Bim mRNA increased less than 2-fold, BIM protein increased more than 10-fold after Epo withdrawal, suggesting post-transcriptional regulation of BIM. Epo treatment resulted in rapid phosphorylation of BIM at Serine 65 and phosphorylation correlated with degradation of BIM. Inhibition of ERK (extracellular signal-regulated kinase) by a MEK/ERK inhibitor, U0126, blocked both phosphorylation and degradation of BIM, resulting in apoptosis. Treatment with a proteasome inhibitor, MG-132, also blocked degradation of phosphorylated BIM. Down-regulation of BIM with the shRNA resulted in HCD57 cells more resistant to apoptosis induced by either Epo withdrawal or ERK inhibition. Although we observed no significant changes in the number of erythrocytes or reticulocytes in the circulation of Bim−/− mice, erythroid progenitors from bone marrow in Bim−/− mice were reduced in number and more resistant to apoptosis induced by U0126 MEK/ERK inhibitor. Epo protects erythroid cells from apoptosis in part through ERK-mediated phosphorylation followed by proteasomal degradation of BIM.
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影响因子：
20.3
作者：
Halupa, A;Bailey, ML;Barber, DL
通讯作者：
Barber, DL
影响因子：
20.3
作者：
Bao, HF;Jacobs-Helber, SM;Sawyer, ST
通讯作者：
Sawyer, ST
影响因子：
5.3
作者：
Jacobs-Helber, SM;Wickrema, A;Sawyer, ST
通讯作者：
Sawyer, ST
影响因子：
4.8
作者：
JacobsHelber, SM;Penta, K;Sawyer, ST
通讯作者：
Sawyer, ST
影响因子：
8.3
作者：
Kannel, William B.;Gordon, Tavia;McNamara, Patricia
通讯作者：
McNamara, Patricia