Molecular basis for Nse5-6 mediated regulation of Smc5/6 functions Journal Article
| Authors: | Li, S.; Yu, Y.; Zheng, J.; Miller-Browne, V.; Ser, Z.; Kuang, H.; Patel, D. J.; Zhao, X. |
| Article Title: | Molecular basis for Nse5-6 mediated regulation of Smc5/6 functions |
| Abstract: | The Smc5/6 complex (Smc5/6) is important for genome replication and repair in eukaryotes. Its cellular functions are closely linked to the ATPase activity of the Smc5 and Smc6 subunits. This activity requires the dimerization of the motor domains of the two SMC subunits and is regulated by the six non-SMC subunits (Nse1 to Nse6). Among the NSEs, Nse5 and Nse6 form a stable subcomplex (Nse5-6) that dampens the ATPase activity of the complex. However, the underlying mechanisms and biological significance of this regulation remain unclear. Here, we address these issues using structural and functional studies. We determined cryo-EM structures of the yeast Smc5/6 derived from complexes consisting of either all eight subunits or a subset of five subunits. Both structures reveal that Nse5-6 associates with Smc6’s motor domain and the adjacent coiled-coil segment, termed the neck region. Our structural analyses reveal that this binding is compatible with motor domain dimerization but results in dislodging the Nse4 subunit from the Smc6 neck. As the Nse4-Smc6 neck interaction favors motor domain engagement and thus ATPase activity, Nse6’s competition with Nse4 can explain how Nse5-6 disfavors ATPase activity. Such regulation could in principle differentially affect Smc5/6-mediated processes depending on their needs of the complex’s ATPase activity. Indeed, mutagenesis data in cells provide evidence that the Nse6-Smc6 neck interaction is important for the resolution of DNA repair intermediates but not for replication termination. Our results thus provide a molecular basis for how Nse5-6 modulates the ATPase activity and cellular functions of Smc5/6. Copyright © 2023 the Author(s). |
| Keywords: | protein expression; genetics; nonhuman; dna replication; genetic analysis; polymerase chain reaction; protein function; cell cycle protein; nonhistone protein; electron microscopy; metabolism; cell cycle proteins; chromosomal proteins, non-histone; gene; homologous recombination; cell function; dna repair; molecular dynamics; structure activity relation; protein purification; saccharomyces cerevisiae; gene interaction; western blotting; immunoprecipitation; immunoblotting; gene control; yeast; structure analysis; bioinformatics; adenosine triphosphatase; adenosine triphosphatases; protein synthesis regulation; cryo-em; smc5/6; article; humidity; smc; nse5; nse6; smc5; nse5-6; smc6 |
| Journal Title: | Proceedings of the National Academy of Sciences of the United States of America |
| Volume: | 120 |
| Issue: | 45 |
| ISSN: | 0027-8424 |
| Publisher: | National Academy of Sciences |
| Date Published: | 2023-11-07 |
| Start Page: | e2310924120 |
| Language: | English |
| DOI: | 10.1073/pnas.2310924120 |
| PUBMED: | 37903273 |
| PROVIDER: | scopus |
| PMCID: | PMC10636319 |
| DOI/URL: | |
| Notes: | Article -- MSK Cancer Center Support Grant (P30 CA008748) acknowledged in PubMed -- MSK corresponding authors are Dinshaw Patel and Xiaolan Zhao -- Source: Scopus |
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