3t5v
From Proteopedia
Sac3:Thp1:Sem1 complex
Structural highlights
Function[SAC3_YEAST] Component of the SAC3-THP1 complex, which functions in transcription-coupled mRNA export from the nucleus to the cytoplasm. SAC3-THP1 functions in docking export-competent ribonucleoprotein particles (mRNPs) to the nuclear entrance of the nuclear pore complex (nuclear basket), by association with components of the nuclear mRNA export machinery (MEX67-MTR2 and SUB2) in the nucleoplasm and the nucleoporin NUP1 at the nuclear basket.[1] [2] [SEM1_YEAST] Versatile protein that might stabilize multiple protein complexes involved in diverse pathways. Subunit of the 26S proteasome which plays a role in ubiquitin-dependent proteolysis. Associates also with the TREX-2 complex that is required for transcription-coupled mRNA export, and the COP9 signalosome, which is involved in deneddylation.[3] [4] [THP1_YEAST] Component of the SAC3-THP1 complex, which functions in transcription-coupled mRNA export from the nucleus to the cytoplasm. SAC3-THP1 functions in docking export-competent ribonucleoprotein particles (mRNPs) to the nuclear entrance of the nuclear pore complex (nuclear basket), by association with components of the nuclear mRNA export machinery (MEX67-MTR2 and SUB2) in the nucleoplasm and the nucleoporin NUP1 at the nuclear basket. THP1 binds to RNA in vitro.[5] [6] [7] Publication Abstract from PubMedThe conserved TREX-2 transcription-export complex integrates transcription and processing of many actively transcribed nascent mRNAs with the recruitment of export factors at nuclear pores and also contributes to transcriptional memory and genomic stability. We report the crystal structure of the Sac3-Thp1-Sem1 segment of Saccharomyces cerevisiae TREX-2 that interfaces with the gene expression machinery. Sac3-Thp1-Sem1 forms a previously uncharacterized PCI-domain complex characterized by the juxtaposition of Sac3 and Thp1 winged helix domains, forming a platform that mediates nucleic acid binding. Our structure-guided mutations support the idea that the Thp1-Sac3 interaction is an essential requirement for mRNA binding and for the coupling of transcription and processing to mRNP assembly and export. These results provide insight into how newly synthesized transcripts are efficiently transferred from TREX-2 to the principal mRNA export factor, and they reveal how Sem1 stabilizes PCI domain-containing proteins and promotes complex assembly. Structural basis for the assembly and nucleic acid binding of the TREX-2 transcription-export complex.,Ellisdon AM, Dimitrova L, Hurt E, Stewart M Nat Struct Mol Biol. 2012 Feb 19;19(3):328-36. doi: 10.1038/nsmb.2235. PMID:22343721[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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