5fir
Crystal structure of C. elegans XRN2 in complex with the XRN2-binding domain of PAXT-1
Structural highlights
FunctionXRN2_CAEEL Possesses 5'->3' exoribonuclease activity. Plays a role in maintenance of steady-state concentration and turnover of microRNAs (miRNA) by degradation of mature miRNA. Partially redundant to xrn-1 in miRNA guide strand degradation. Implicated in differential regulation of mRNAs such as let-7 by controlling the accumulation of mature miRNA. Positively regulates molting of the pharyngeal cuticle.[1] [2] Publication Abstract from PubMedThe RNase XRN2 is essential in RNA metabolism. In Caenorhabditis elegans, XRN2 functions with PAXT-1, which shares a putative XRN2-binding domain (XTBD) with otherwise unrelated mammalian proteins. Here, we characterize the structure and function of an XTBD-XRN2 complex. Although XTBD stably interconnects two XRN2 domains through numerous interacting residues, mutation of a single critical residue suffices to disrupt XTBD-XRN2 complexes in vitro and to recapitulate paxt-1-null mutant phenotypes in vivo. Demonstrating conservation of function, vertebrate XTBD-containing proteins bind XRN2 in vitro, and human CDKN2AIPNL (HsC2AIL) can substitute for PAXT-1 in vivo. In vertebrates, which express three distinct XTBD-containing proteins, XRN2 may partition into distinct stable heterodimeric complexes, which probably differ in subcellular localization or function. In C. elegans, complex formation with PAXT-1, the sole XTBD protein, serves to preserve the stability of XRN2 in the absence of substrate. Structural basis and function of XRN2 binding by XTB domains.,Richter H, Katic I, Gut H, Grosshans H Nat Struct Mol Biol. 2016 Jan 18. doi: 10.1038/nsmb.3155. PMID:26779609[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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