Abstract
The eukaryotic Sm and the Sm-like (LSm) proteins form a large family that includes LSm proteins in archaea and the Hfq proteins in bacteria. Commonly referred to as the (L)Sm protein family, the various members play important roles in RNA processing, decay, and riboregulation. Particularly interesting from a structural point of view is their ability to assemble into doughnut-shaped rings, which allows them to bind preferentially the uridine-rich 3′-end of RNA oligonucleotides. With an emphasis on Hfq, this review compares the RNA-binding properties of the various (L)Sm rings that were recently co-crystallized with RNA substrates, and it discusses how these properties relate to physiological function.
Disclosure of Potential Conflicts of Interest
No potential conflicts of interest were disclosed.
Acknowledgments
I am very grateful to Evelyn Sauer and I thank Regina Büttner for their scientific contributions to our work on Hfq over the past 6 y. I also thank Jörg Vogel for getting us started on the topic in the context of the DFG Priority Program SPP1258 (Sensory and Regulatory RNAs in Prokaryotes). Scientific exchange and funding via the DFG SPP1258 Priority Program is gratefully acknowledged. I also thank the members of the group and of the department for discussions as well as Elisa Izaurralde and the Max Planck Society for continued support.