3fwc
From Proteopedia
Sac3:Sus1:Cdc31 complex
Structural highlights
Function[CDC31_YEAST] Functions as a component of the nuclear pore complex (NPC) and the spindle pole body (SPB) half-bridge. At the SPB, it is recruited by KAR1 and MPS3 to the SPB half-bridge and involved in the initial steps of SPB duplication. It probably plays a similar role in de novo assembly of NPCs at the nuclear envelope. Also involved in connection with the protein kinase KIC1 in the maintenance of cell morphology and integrity.[1] [2] [3] [4] [5] [6] [SUS1_YEAST] Involved in mRNA export coupled transcription activation by association with both the TREX-2 and the SAGA complexes. The transcription regulatory histone acetylation (HAT) complex SAGA is involved in RNA polymerase II-dependent regulation of approximately 10% of yeast genes. At the promoters, SAGA is required for recruitment of the basal transcription machinery. It influences RNA polymerase II transcriptional activity through different activities such as TBP interaction (SPT3, SPT8 and SPT20) and promoter selectivity, interaction with transcription activators (GCN5, ADA2, ADA3 and TRA1), and chromatin modification through histone acetylation (GCN5) and deubiquitination (UBP8). SUS1 forms a distinct functional SAGA module with UBP8, SGF11 and SGF73 required for deubiquitination of H2B and for the maintenance of steady-state H3 methylation levels. The TREX-2 complex 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. TREX-2 participates in mRNA export and accurate chromatin positioning in the nucleus by tethering genes to the nuclear periphery. SUS1 has also a role in mRNP biogenesis and maintenance of genome integrity through preventing RNA-mediated genome instability. Finally SUS1 has a role in response to DNA damage induced by methyl methane sulfonate (MMS) and replication arrest induced by hydroxyurea.[7] [8] [9] [10] [11] [12] [13] [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.[14] [15] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe yeast Sac3:Cdc31:Sus1:Thp1 (TREX-2) complex facilitates the repositioning and association of actively transcribing genes with nuclear pores (NPCs)-"gene gating"-that is central to integrating transcription, processing, and mRNA nuclear export. We present here the crystal structure of Sus1 and Cdc31 bound to a central region of Sac3 (the CID domain) that is crucial for its function. Sac3(CID) forms a long, gently undulating alpha helix around which one Cdc31 and two Sus1 chains are wrapped. Sus1 has an articulated helical hairpin fold that facilitates its wrapping around Sac3. In vivo studies using engineered mutations that selectively disrupted binding of individual chains to Sac3 indicated that Sus1 and Cdc31 function synergistically to promote NPC association of TREX-2 and mRNA nuclear export. These data indicate Sac3(CID) provides a scaffold within TREX-2 to integrate interactions between protein complexes to facilitate the coupling of transcription and mRNA export during gene expression. Sus1, Cdc31, and the Sac3 CID region form a conserved interaction platform that promotes nuclear pore association and mRNA export.,Jani D, Lutz S, Marshall NJ, Fischer T, Kohler A, Ellisdon AM, Hurt E, Stewart M Mol Cell. 2009 Mar 27;33(6):727-37. PMID:19328066[16] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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Categories: Atcc 18824 | Large Structures | Jani, D | Stewart, M | Acetylation | Calcium | Cell cycle | Cell division | Complex | Gene gating | Mitosis | Mrna transport | Nuclear pore complex | Nucleus | Phosphoprotein | Protein transport | Transcription | Transcription regulation | Translocation | Transport
