Archaeal and eukaryotic homologs of Hfq A structural and evolutionary perspective on Sm function
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چکیده
A history of the Sm/Lsm-SmAP-Hfq family. Human Sm proteins were discovered over 30 y ago as a group of small antigens involved in the autoimmune disease systemic lupus erythematosus. The ≈80-residue proteins were identified in association with ribonucleoprotein (RNP) complexes from eukaryotic cellular extracts. Other early work uncovered vital roles for Sm proteins in forming the cores of the uracil-rich small nuclear RNPs (U snRNPs) that further assemble into spliceosomes and excise introns in eukaryotic pre-mRNAs (reviewed in ref. 5). Over the ensuing decades, great strides in elucidating the physiological and biochemical properties of Sm proteins, as well as the threedimensional (3D) structures and assembly behavior of these RNA-associated proteins, led to our current view that eukaryotic Sm proteins function as molecular scaffolds for RNP assembly. As depicted in Figure 1A, eukaryotic Sm assemblies act in a vast
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Archaeal and eukaryotic homologs of Hfq
Hfq and other Sm proteins are central in RNA metabolism, forming an evolutionarily conserved family that plays key roles in RNA processing in organisms ranging from archaea to bacteria to human. Sm-based cellular pathways vary in scope from eukaryotic mRNA splicing to bacterial quorum sensing, with at least one step in each of these pathways being mediated by an RNA-associated molecular assembl...
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