5fu7
drosophila nanos NBR peptide bound to the NOT module of the human CCR4-NOT complex
Structural highlights
FunctionCNOT1_HUMAN Belongs to the CCR4-NOT complex that functions as general transcription regulation complex. Acts as a transcriptional repressor. Represses the ligand-dependent transcriptional activation by nuclear receptors.[1] [2] Publication Abstract from PubMedNanos proteins repress the expression of target mRNAs by recruiting effector complexes through non-conserved N-terminal regions. In vertebrates, Nanos proteins interact with the NOT1 subunit of the CCR4-NOT effector complex through a NOT1 interacting motif (NIM), which is absent in Nanos orthologs from several invertebrate species. Therefore, it has remained unclear whether the Nanos repressive mechanism is conserved and whether it also involves direct interactions with the CCR4-NOT deadenylase complex in invertebrates. Here, we identify an effector domain (NED) that is necessary for the Drosophila melanogaster (Dm) Nanos to repress mRNA targets. The NED recruits the CCR4-NOT complex through multiple and redundant binding sites, including a central region that interacts with the NOT module, which comprises the C-terminal domains of NOT1-3. The crystal structure of the NED central region bound to the NOT module reveals an unanticipated bipartite binding interface that contacts NOT1 and NOT3 and is distinct from the NIM of vertebrate Nanos. Thus, despite the absence of sequence conservation, the N-terminal regions of Nanos proteins recruit CCR4-NOT to assemble analogous repressive complexes. Distinct modes of recruitment of the CCR4-NOT complex by Drosophila and vertebrate Nanos.,Raisch T, Bhandari D, Sabath K, Helms S, Valkov E, Weichenrieder O, Izaurralde E EMBO J. 2016 May 2;35(9):974-90. doi: 10.15252/embj.201593634. Epub 2016 Mar 11. PMID:26968986[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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