Structural Characterization of the Chaetomium thermophilum TREX-2 Complex and its Interaction with the mRNA Nuclear Export Factor Mex67:Mtr2.Dimitrova, L., Valkov, E., Aibara, S., Flemming, D., McLaughlin, S.H., Hurt, E., Stewart, M.
(2015) Structure 23: 1246-1257
- PubMed: 26051714
- DOI: 10.1016/j.str.2015.05.002
- Primary Citation of Related Structures:
- PubMed Abstract:
The TREX-2 complex integrates mRNA nuclear export into the gene expression pathway and is based on a Sac3 scaffold to which Thp1, Sem1, Sus1, and Cdc31 bind. TREX-2 also binds the mRNA nuclear export factor, Mex67:Mtr2, through the Sac3 N-terminal re ...
The TREX-2 complex integrates mRNA nuclear export into the gene expression pathway and is based on a Sac3 scaffold to which Thp1, Sem1, Sus1, and Cdc31 bind. TREX-2 also binds the mRNA nuclear export factor, Mex67:Mtr2, through the Sac3 N-terminal region (Sac3N). Here, we characterize Chaetomium thermophilum TREX-2, show that the in vitro reconstituted complex has an annular structure, and define the structural basis for interactions between Sac3, Sus1, Cdc31, and Mex67:Mtr2. Crystal structures show that the binding of C. thermophilum Sac3N to the Mex67 NTF2-like domain (Mex67(NTF2L)) is mediated primarily through phenylalanine residues present in a series of repeating sequence motifs that resemble those seen in many nucleoporins, and Mlp1 also binds Mex67:Mtr2 using a similar motif. Deletion of Sac3N generated growth and mRNA export defects in Saccharomyces cerevisiae, and we propose TREX-2 and Mlp1 function to facilitate export by concentrating mature messenger ribonucleoparticles at the nuclear pore entrance.
Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK; Biochemie-Zentrum der Universität Heidelberg, INF328, 69120 Heidelberg, Germany.