Structure of a Human 4E-T/DDX6/CNOT1 Complex Reveals the Different Interplay of DDX6-Binding Proteins with the CCR4-NOT Complex.
The DEAD-box protein DDX6 is a central component of translational repression mechanisms in maternal mRNA storage in oocytes and microRNA-mediated silencing in somatic cells. DDX6 interacts with the CCR4-NOT complex and functions in concert with several post-transcriptional regulators, including Edc3, Pat1, and 4E-T. We show that the conserved CUP-homology domain (CHD) of human 4E-T interacts directly with DDX6 in both the presence and absence of the central MIF4G domain of CNOT1. The 2.1-Å resolution structure of the corresponding ternary complex reveals how 4E-T CHD wraps around the RecA2 domain of DDX6 and contacts CNOT1. Although 4E-T CHD lacks recognizable sequence similarity with Edc3 or Pat1, it shares the same DDX6-binding surface. In contrast to 4E-T, however, the Edc3 and Pat1 FDF motifs dissociate from DDX6 upon CNOT1 MIF4G binding in vitro. The results underscore the presence of a complex network of simultaneous and/or mutually exclusive interactions in DDX6-mediated repression.
Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried/Munich, Germany.
Sevim
S
Ozgur
Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried/Munich, Germany.
Jérôme
J
Basquin
Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
Anastasiia
A
Kamenska
Friedrich Miescher Institute for Biomedical Research, Maulberstrasse 66, 4058 Basel, Switzerland.
Witold
W
Filipowicz
Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
Nancy
N
Standart
Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried/Munich, Germany. Electronic address: conti@biochem.mpg.de.
Elena
E
Conti
D001665:Binding Sites / Q000235:genetics / Q000502:physiology; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D053487:DEAD-box RNA Helicases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D017433:Protein Structure, Secondary; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054398:Receptors, CCR4 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
C528690:CNOT1 protein, human; D002352:Carrier Proteins; C411571:EIF4ENIF1 protein, human; C539882:NR4A2 protein, human; D057126:Nuclear Receptor Subfamily 4, Group A, Member 2; D029543:Nucleocytoplasmic Transport Proteins; D011518:Proto-Oncogene Proteins; D054398:Receptors, CCR4; D014157:Transcription Factors; C094683:DDX6 protein, human; D053487:DEAD-box RNA Helicases