4ct7 | pdb_00004ct7
CNOT9-CNOT1 complex with bound tryptophan
Structural highlights
Function[CNOT1_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] [RCD1_HUMAN] Component of the CCR4-NOT complex which is one of the major cellular mRNA deadenylases and is linked to various cellular processes including bulk mRNA degradation, miRNA-mediated repression, translational repression during translational initiation and general transcription regulation. Additional complex functions may be a consequence of its influence on mRNA expression. Involved in down-regulation of MYB- and JUN-dependent transcription. May play a role in cell differentiation (By similarity). Can bind oligonucleotides, such as poly-G, poly-C or poly-T (in vitro), but the physiological relevance of this is not certain. Does not bind poly-A. Enhances ligand-dependent transcriptional activity of nuclear hormone receptors, including RARA, expect ESR1-mediated transcription that is not only slightly increased, if at all.[3] [4] Publication Abstract from PubMedMicroRNAs (miRNAs) control gene expression by regulating mRNA translation and stability. The CCR4-NOT complex is a key effector of miRNA function acting downstream of GW182/TNRC6 proteins. We show that miRNA-mediated repression requires the central region of CNOT1, the scaffold protein of CCR4-NOT. A CNOT1 domain interacts with CNOT9, which in turn interacts with the silencing domain of TNRC6 in a tryptophan motif-dependent manner. These interactions are direct, as shown by the structure of a CNOT9-CNOT1 complex with bound tryptophan. Another domain of CNOT1 with an MIF4G fold recruits the DEAD-box ATPase DDX6, a known translational inhibitor. Structural and biochemical approaches revealed that CNOT1 modulates the conformation of DDX6 and stimulates ATPase activity. Structure-based mutations showed that the CNOT1 MIF4G-DDX6 interaction is important for miRNA-mediated repression. These findings provide insights into the repressive steps downstream of the GW182/TNRC6 proteins and the role of the CCR4-NOT complex in posttranscriptional regulation in general. Structural and Biochemical Insights to the Role of the CCR4-NOT Complex and DDX6 ATPase in MicroRNA Repression.,Mathys H, Basquin J, Ozgur S, Czarnocki-Cieciura M, Bonneau F, Aartse A, Dziembowski A, Nowotny M, Conti E, Filipowicz W Mol Cell. 2014 Apr 22. pii: S1097-2765(14)00269-X. doi:, 10.1016/j.molcel.2014.03.036. PMID:24768538[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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