BTG2 antiproliferative protein interacts with the human CCR4 complex existing in vivo in three cell-cycle-regulated forms.
The yeast CCR4-NOT complex exists in two forms (1.0 and 1.9 MDa) that share several common subunits, including yCCR4, yCAF1 and five NOT proteins (NOT1-5). Here, we report that different complexes containing mammalian homologs of CCR4-NOT subunits exist in mammalian cells, with estimated sizes of approximately 1.9 MDa, approximately 1 MDa and approximately 650 kDa, and that BTG2, a member of a protein family with antiproliferative functions, can associate with these complexes. Immunoprecipitation and gel filtration experiments established that BTG2 interacts in vivo with hCCR4 protein via hCAF1 and hPOP2. Moreover, we show that hCCR4, as well as hCAF1 and BTG2, modulate the transcription regulation mediated by ERalpha. Finally, we demonstrate that the cellular localization of hCAF1 and the cell content in hCAF1-containing complexes change as cells progress from quiescence to S phase. These findings suggest that the different regulatory pathways in which hCAF1 is involved, notably transcription regulation and mRNA turnover, may occur through distinct CCR4 complexes in the course of cell-cycle progression.
Morel
Anne-Pierre
AP
Unité INSERM U590, Centre Léon Bérard, 69373 Lyon Cedex 08, France.
Sentis
Stéphanie
S
Bianchin
Claire
C
Le Romancer
Muriel
M
Jonard
Laurence
L
Rostan
Marie-Claude
MC
Rimokh
Ruth
R
Corbo
Laura
L
D002453:Cell Cycle; D002469:Cell Separation; D002850:Chromatography, Gel; D003593:Cytoplasm / Q000378:metabolism; D047628:Estrogen Receptor alpha; D005434:Flow Cytometry; D017930:Genes, Reporter; D016147:Genes, Tumor Suppressor / Q000502:physiology*; D005822:Genetic Vectors; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism / Q000502:physiology*; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D011233:Precipitin Tests; D011485:Protein Binding; D011506:Proteins; D012333:RNA, Messenger / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D016196:S Phase; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D025521:Tumor Suppressor Proteins; D020798:Two-Hybrid System Techniques
C489780:CNOT8 protein, human; D047628:Estrogen Receptor alpha; D017874:Immediate-Early Proteins; D011506:Proteins; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D011994:Recombinant Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C070114:BTG2 protein, human; D005982:Glutathione Transferase