Human antigen R (HuR) is a key regulator of cellular mRNAs containing adenylate/uridylate-rich elements (AU-rich elements; AREs). These are a major class of cis elements within 3' untranslated regions, targeting these mRNAs for rapid degradation. HuR contains three RNA recognition motifs (RRMs): a tandem RRM1 and 2, followed by a flexible linker and a C-terminal RRM3. While RRM1 and 2 are structurally characterized, little is known about RRM3. Here we present a 1.9-Å-resolution crystal structure of RRM3 bound to different ARE motifs. This structure together with biophysical methods and cell-culture assays revealed the mechanism of RRM3 ARE recognition and dimerization. While multiple RNA motifs can be bound, recognition of the canonical AUUUA pentameric motif is possible by binding to two registers. Additionally, RRM3 forms homodimers to increase its RNA binding affinity. Finally, although HuR stabilizes ARE-containing RNAs, we found that RRM3 counteracts this effect, as shown in a cell-based ARE reporter assay and by qPCR with native HuR mRNA targets containing multiple AUUUA motifs, possibly by competing with RRM12.

• MeSH
• 3' nepřekládaná oblast MeSH
• dimerizace MeSH
• encefalomyelitida paraneoplastická - Hu antigeny chemie   MeSH
• HuR protein chemie   genetika   MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• motiv rozpoznávající RNA genetika   MeSH
• nádorové supresorové proteiny chemie   MeSH
• proteiny vázající RNA chemie   genetika   MeSH
• ribonukleosiddifosfátreduktasa chemie   MeSH
• úseky bohaté na AU genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH