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Erythroid differentiation‐associated gene interacts with NPM1 (nucleophosmin/B23) and increases its protein stability, resisting cell apoptosis
Author(s) -
Zhang MeiJiang,
Ding YaLi,
Xu ChengWang,
Yang Yang,
Lian WenXi,
Zhan YiQun,
Li Wei,
Xu WangXiang,
Yu Miao,
Ge ChangHui,
Ning HongMei,
Li ChangYan,
Yang XiaoMing
Publication year - 2012
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2012.08663.x
Subject(s) - nucleophosmin , npm1 , gene knockdown , biology , microbiology and biotechnology , k562 cells , cancer research , apoptosis , gene , biochemistry , myeloid leukemia , karyotype , chromosome
Erythroid differentiation‐associated gene (EDAG) is a haematopoietic tissue‐specific transcription regulator that plays a key role in maintaining the homeostasis of haematopoietic lineage commitment. In acute myeloid leukaemia (AML) patients, the high expression level of EDAG is associated with poor prognosis. NPM1 (nucleophosmin/B23), a ubiquitous nucleolar phosphoprotein, comprises a multifunctional protein that is involved in several cellular processes, including ribosome biogenesis, centrosome duplication, cell cycle progression, cell growth and transformation. Various studies have implicated NPM1 overexpression in promoting tumour cell proliferation, blocking the differentiation of leukaemia cells and resisting apoptosis. In the present study, using co‐immunoprecipitation, we characterized EDAG as a physiological binding partner of NPM1; The N‐terminal (amino acids 1–124) region of EDAG interacts with the N‐terminal (amino acids 118–187) of NPM1. Under cycloheximide treatment, the stability of NPM1 protein was enhanced by EDAG overexpression, whereas knockdown of EDAG by lentivirus‐mediated small interfering RNA resulted in an increased degradation rate of NPM1 in K562 cells. During 4β‐phorbol l2‐myristate 13‐acetate‐induced K562 megakaryocytic differentiation, overexpression of EDAG prevented the down‐regulation of NPM1 proteins, whereas knockdown of EDAG accelerated the down‐regulation of NPM1. EDAG deletion mutant lacking the binding domain with NPM1 lost the ability to stabilize NPM1 protein. Furthermore, knockdown of EDAG in K562 cells led to increased cell apoptosis induced by imatinib, and re‐expression of NPM1 attenuated the increased apoptosis. These results suggest that EDAG enhances the protein stability of NPM1 via binding to NPM1, which plays a critical role in the anti‐apoptosis of leukaemia cells. Structured digital abstract• NPM1 physically interacts with EDAG by anti bait coimmunoprecipitation ( View interaction ) • EDAG physically interacts with HSPA1A , UBTF , SP100 , NPM1 , HNRPA3 , MCM3 , UBE1 , FBL , ZnF20 , ZnF25 and MNDA by anti bait coimmunoprecipitation ( View interaction ) • EDAG physically interacts with NPM1 by anti tag coimmunoprecipitation (View Interaction: 1 , 2 , 3 ) • EDAG and NPM1 colocalize by fluorescence microscopy (View Interaction: 1 , 2 )