8U8D

Cryo-EM structure of the TREX-2 complex in complex with the N-terminal motif of Sub2

Summary for 8U8D

• Entry DOI: 10.2210/pdb8u8d/pdb
• EMDB information: 42021 42022
• Descriptor: Nuclear mRNA export factor, THP1 isoform 1, 26S proteasome complex subunit SEM1, ... (4 entities in total)
• Functional Keywords: mrna nuclear export, rna binding protein
• Biological source: Saccharomyces cerevisiae (brewer's yeast); More
• Total number of polymer chains: 4
• Total formula weight: 171444.00

Authors

Clarke, B.P.,Xie, Y.,Ren, Y. (deposition date: 2023-09-17, release date: 2025-02-05, Last modification date: 2025-03-19)

Primary citation

Xie, Y.,Clarke, B.P.,Xie, D.,Mei, M.,Bhat, P.,Hill, P.S.,Angelos, A.E.,Cagatay, T.,Haider, M.,Collier, S.E.,Chambers, M.G.,Aksenova, V.,Dasso, M.,Fontoura, B.M.A.,Ren, Y.
Structures and mRNP remodeling mechanism of the TREX-2 complex.
Structure, 33:566-582.e6, 2025

PubMed Abstract: mRNAs are packaged with proteins into messenger ribonucleoprotein complexes (mRNPs) in the nucleus. mRNP assembly and export are of fundamental importance for all eukaryotic gene expression. Before export to the cytoplasm, mRNPs undergo dynamic remodeling governed by the DEAD-box helicase DDX39B (yeast Sub2). DDX39B/Sub2 primarily functions in the nucleus and leaves the mRNP prior to export through the nuclear pore complex; however, the underlying mechanisms remain elusive. Here, we identify the conserved TREX-2 complex as the long-sought factor that facilitates DDX39B/Sub2 to complete the mRNP remodeling cycle. Our crystallographic and cryoelectron microscopy (cryo-EM) analyses demonstrate that TREX-2 modulates the activities of DDX39B/Sub2 through multiple interactions. Critically, a conserved "trigger loop" from TREX-2 splits the two RecA domains of DDX39B/Sub2 and promotes the removal of DDX39B/Sub2 from mRNP. Our findings suggest that TREX-2 coordinates with DDX39B/Sub2 and the human export receptor NXF1-NXT1 (yeast Mex67-Mtr2) to complete the final steps of nuclear mRNP assembly.

PubMed: 39862860
DOI: 10.1016/j.str.2024.12.019

Experimental method

ELECTRON MICROSCOPY (3.04 Å)