Components of the CCR4-NOT complex function as nuclear hormone receptor coactivators via association with the NRC-interacting Factor NIF-1.
CCR4-NOT is an evolutionarily conserved, multicomponent complex known to be involved in transcription as well as mRNA degradation. Various subunits (e.g. CNOT1 and CNOT7/CAF1) have been reported to be involved in influencing nuclear hormone receptor activities. Here, we show that CCR4/CNOT6 and RCD1/CNOT9, members of the CCR4-NOT complex, potentiate nuclear receptor activity. RCD1 interacts in vivo and in vitro with NIF-1 (NRC-interacting factor), a previously characterized nuclear receptor cotransducer that activates nuclear receptors via its interaction with NRC. As with NIF-1, RCD1 and CCR4 do not directly associate with nuclear receptors; however, they enhance ligand-dependent transcriptional activation by nuclear hormone receptors. CCR4 mediates its effect through the ligand binding domain of nuclear receptors and small interference RNA-mediated silencing of endogenous CCR4 results in a marked decrease in nuclear receptor activation. Furthermore, knockdown of CCR4 results in an attenuated stimulation of RARalpha target genes (e.g. Sox9 and HoxA1) as shown by quantitative PCR assays. The silencing of endogenous NIF-1 also resulted in a comparable decrease in the RAR-mediated induction of both Sox9 and HoxA1. Furthermore, CCR4 associates in vivo with NIF-1. In addition, the CCR4-enhanced transcriptional activation by nuclear receptors is dependent on NIF-1. The small interference RNA-mediated knockdown of NIF-1 blocks the ligand-dependent potentiating effect of CCR4. Our results suggest that CCR4 plays a role in the regulation of certain endogenous RARalpha target genes and that RCD1 and CCR4 might mediate their function through their interaction with NIF-1.
Garapaty
Shivani
S
Department of Pharmacology and Medicine, New York University School of Medicine, New York, New York 10016, USA.
Mahajan
Muktar A
MA
Samuels
Herbert H
HH
D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006367:HeLa Cells; D006609:High Mobility Group Proteins / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008024:Ligands; D008954:Models, Biological; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D055758:SOX9 Transcription Factor; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D020798:Two-Hybrid System Techniques
C468527:CNOT9 protein, human; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D009687:Nuclear Proteins; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; D014157:Transcription Factors; C466083:ZNF335 protein, human