JNK-mediated turnover and stabilization of the transcription factor p45/NF-E2 during differentiation of murine erythroleukemia cells.
Regulation of the homeostatic concentrations of specific sets of transcription factors is essential for correct programming of cell proliferation and differentiation. We have characterized the signal transduction pathways regulating the catabolisis of p45/NF-E2, a bZIP factor activating the erythroid and megakaryocytic gene transcription. Through use of different approaches including nano-scale proteomics, we show that activated-JNK, or Phospho-JNK (P-JNK), physically interacts with p45/NF-E2 and phosphorylates its Ser157 residue. This reaction leads to the poly-ubiquitination of p45/NF-E2 at one or more of six Lys residues, one of which being also a sumoylation site, and its degradation through the proteasome pathway. Significantly, this regulatory pathway of p45/NF-E2 by P-JNK exists only in uninduced murine erythroleukemia (MEL) cells but not in differentiated MEL cells in which JNK is inactivated on DMSO induction. Based on the above data and analysis of the chromatin-binding kinetics of p45/NF-E2 and the erythroid gene repressor Bach1 during the early phase of MEL differentiation, we suggest a model for the regulation of erythroid maturation. In the model, the posttranslational modifications and turnover of p45/NF-E2, as mediated by P-JNK, contribute to the control of its homeostatic concentration and consequently, its regulatory functions in the progression of erythroid differentiation and erythroid gene expression.
Lee
Tung-Liang
TL
Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, Republic of China.
Shyu
Yu-Chiau
YC
Hsu
Pang-Hung
PH
Chang
Chiung-Wen
CW
Wen
Shau-Ching
SC
Hsiao
Wei-Yuan
WY
Tsai
Ming-Daw
MD
Shen
Che-Kun James
CK
D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D045744:Cell Line, Tumor; D051856:Fanconi Anemia Complementation Group Proteins / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism*; D051379:Mice; D050984:NF-E2 Transcription Factor, p45 Subunit / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
C102108:BACH1 protein, human; D050976:Basic-Leucine Zipper Transcription Factors; D051856:Fanconi Anemia Complementation Group Proteins; D050984:NF-E2 Transcription Factor, p45 Subunit; D011993:Recombinant Fusion Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D046988:Proteasome Endopeptidase Complex