Structural and biochemical analysis of a NOT1 MIF4G-like domain of the CCR4-NOT complex.
Raisch, T., Sandmeir, F., Weichenrieder, O., Valkov, E., Izaurralde, E.(2018) J Struct Biol 204: 388-395
- PubMed: 30367941 
- DOI: https://doi.org/10.1016/j.jsb.2018.10.009
- Primary Citation of Related Structures:  
6H3Z - PubMed Abstract: 
The CCR4-NOT complex plays a central role in the regulation of gene expression and degradation of messenger RNAs. The multisubunit complex assembles on the NOT1 protein, which acts as a 'scaffold' and is highly conserved in eukaryotes. NOT1 consists of a series of helical domains that serve as docking sites for other CCR4-NOT subunits. We describe a crystal structure of a connector domain of NOT1 from the thermophilic fungus Chaetomium thermophilum (Ct). Comparative structural analysis indicates that this domain adopts a MIF4G-like fold and we have termed it the MIF4G-C domain. Solution scattering studies indicate that the human MIF4G-C domain likely adopts a very similar fold to the Ct MIF4G-C. MIF4G domains have been described to mediate interactions with DEAD-box helicases such as DDX6. However, comparison of the interfaces of the MIF4G-C with the MIF4G domain of NOT1 that interacts with DDX6 reveals key structural differences that explain why the MIF4G-C does not bind DDX6. We further show that the human MIF4G-C does not interact stably with other subunits of the CCR4-NOT complex. The structural conservation of the MIF4G-C domain suggests that it may have an important but presently undefined role in the CCR4-NOT complex.
Organizational Affiliation: 
Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany.