Functional interaction of transcriptional coactivator ASC-2 and C/EBPalpha in granulocyte differentiation of HL-60 promyelocytic cell.
HL-60 promyelocytic cells were treated with retinoic acid (RA) to stimulate granulocyte differentiation. CCAAT/enhancer binding protein alpha (C/EBPalpha) is known to be the molecular switch during early hematopoietic developmental events that direct cells to the granulocytic pathway. Here we show that the coactivator activating signal cointegrator-2 (ASC-2) plays an important role in differentiation of HL-60 cells into granulocytes by mediating C/EBPalpha-induced gene transcription. The differentiation inducer RA increased mRNA and protein expression of ASC-2. The protein-protein interaction of C/EBPalpha and ASC-2 was detected by coimmunoprecipitation during granulocyte differentiation. Subsequently, GST-pull-down assay revealed that the N-terminal transactivation domain of C/EBPalpha could interact with ASC-2. This functional interaction of ASC-2 with C/EBPalpha drove a synergistic enhancement of C/EBPalpha-dependent transactivation and overexpression of the N-terminal C/EBPalpha protein in HL-60 cells inhibited ASC-2 responsiveness for C/EBPalpha activity in granulocyte differentiation, indicating C/EBPalpha dependency of ASC-2 activity. Taken together, these results suggest that the differentiation-dependent expressed ASC-2 protein physically and functionally interacts with C/EBPalpha and increases its transactivation activity, regulating specific gene transcription for granulocyte differentiation.
Hong
S
S
Hormone Research Center, Chonnam National University, Kwangju, 500-757, Korea.
Lee
M Y
MY
Cheong
J
J
D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D005982:Glutathione Transferase / Q000235:genetics; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018922:HL-60 Cells; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D056918:Nuclear Receptor Coactivators; D011233:Precipitin Tests; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects / Q000502:physiology; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology
D022763:CCAAT-Enhancer-Binding Protein-alpha; D047908:Intracellular Signaling Peptides and Proteins; C486559:NCOA6 protein, human; D056918:Nuclear Receptor Coactivators; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D014212:Tretinoin; D005982:Glutathione Transferase