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-Structure paper
タイトル | The intrinsically disordered TSSC4 protein acts as a helicase inhibitor, placeholder and multi-interaction coordinator during snRNP assembly and recycling. |
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ジャーナル・号・ページ | Nucleic Acids Res, Vol. 50, Issue 5, Page 2938-2958, Year 2022 |
掲載日 | 2022年3月21日 |
著者 | Alexandra Bergfort / Tarek Hilal / Benno Kuropka / İbrahim Avşar Ilik / Gert Weber / Tuğçe Aktaş / Christian Freund / Markus C Wahl / |
PubMed 要旨 | Biogenesis of spliceosomal small nuclear ribonucleoproteins (snRNPs) and their recycling after splicing require numerous assembly/recycling factors whose modes of action are often poorly understood. ...Biogenesis of spliceosomal small nuclear ribonucleoproteins (snRNPs) and their recycling after splicing require numerous assembly/recycling factors whose modes of action are often poorly understood. The intrinsically disordered TSSC4 protein has been identified as a nuclear-localized U5 snRNP and U4/U6-U5 tri-snRNP assembly/recycling factor, but how TSSC4's intrinsic disorder supports TSSC4 functions remains unknown. Using diverse interaction assays and cryogenic electron microscopy-based structural analysis, we show that TSSC4 employs four conserved, non-contiguous regions to bind the PRPF8 Jab1/MPN domain and the SNRNP200 helicase at functionally important sites. It thereby inhibits SNRNP200 helicase activity, spatially aligns the proteins, coordinates formation of a U5 sub-module and transiently blocks premature interaction of SNRNP200 with at least three other spliceosomal factors. Guided by the structure, we designed a TSSC4 variant that lacks stable binding to the PRPF8 Jab1/MPN domain or SNRNP200 in vitro. Comparative immunoprecipitation/mass spectrometry from HEK293 nuclear extract revealed distinct interaction profiles of wild type TSSC4 and the variant deficient in PRPF8/SNRNP200 binding with snRNP proteins, other spliceosomal proteins as well as snRNP assembly/recycling factors and chaperones. Our findings elucidate molecular strategies employed by an intrinsically disordered protein to promote snRNP assembly, and suggest multiple TSSC4-dependent stages during snRNP assembly/recycling. |
リンク | Nucleic Acids Res / PubMed:35188580 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 2.76 - 3.3 Å |
構造データ | EMDB-13045, PDB-7os1: EMDB-13046, PDB-7os2: EMDB-13690, PDB-7px3: |
由来 |
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キーワード | SPLICING / mRNA Splicing / Spliceosomal Assembly / Splicing Regulation / Brr2 Helicase / Spliceosomal biogenesis |