Märtens Birgit, Hou Linlin, Amman Fabian, Wolfinger Michael T, Evguenieva-Hackenberg Elena, Bläsi Udo
Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Center of Molecular Biology, University of Vienna, Vienna Biocenter, Dr. Bohrgasse 9, 1030 Vienna, Austria.
Institute of Microbiology and Molecular Biology, Justus Liebig University Gießen, Heinrich-Buff-Ring 26-32, 35392 Gießen, Germany.
Nucleic Acids Res. 2017 Jul 27;45(13):7938-7949. doi: 10.1093/nar/gkx437.
The conserved Sm and Sm-like proteins are involved in different aspects of RNA metabolism. Here, we explored the interactome of SmAP1 and SmAP2 of the crenarchaeon Sulfolobus solfataricus (Sso) to shed light on their physiological function(s). Both, SmAP1 and SmAP2 co-purified with several proteins involved in RNA-processing/modification, translation and protein turnover as well as with components of the exosome involved in 3΄ to 5΄ degradation of RNA. In follow-up studies a direct interaction with the poly(A) binding and accessory exosomal subunit DnaG was demonstrated. Moreover, elevated levels of both SmAPs resulted in increased abundance of the soluble exosome fraction, suggesting that they affect the subcellular localization of the exosome in the cell. The increased solubility of the exosome was accompanied by augmented levels of RNAs with A-rich tails that were further characterized using RNASeq. Hence, the observation that the Sso SmAPs impact on the activity of the exosome revealed a hitherto unrecognized function of SmAPs in archaea.
保守的Sm蛋白和Sm样蛋白参与RNA代谢的不同方面。在此，我们探索了嗜热栖热菌（Sulfolobus solfataricus，Sso）的SmAP1和SmAP2的相互作用组，以阐明它们的生理功能。SmAP1和SmAP2均与几种参与RNA加工/修饰、翻译和蛋白质周转的蛋白质以及参与RNA 3΄至5΄降解的外泌体成分共同纯化。在后续研究中，证实了它们与聚腺苷酸结合及外泌体辅助亚基DnaG存在直接相互作用。此外，两种SmAP的水平升高导致可溶性外泌体部分的丰度增加，这表明它们影响外泌体在细胞中的亚细胞定位。外泌体溶解度的增加伴随着富含A尾巴的RNA水平的升高，使用RNA测序对其进行了进一步表征。因此，Sso SmAP影响外泌体活性的观察结果揭示了SmAP在古菌中迄今未被认识的功能。
