Structural highlights
FunctionSRP14_HUMAN Signal-recognition-particle assembly has a crucial role in targeting secretory proteins to the rough endoplasmic reticulum membrane. SRP9 together with SRP14 and the Alu portion of the SRP RNA, constitutes the elongation arrest domain of SRP. The complex of SRP9 and SRP14 is required for SRP RNA binding. Publication Abstract from PubMedThe Alu element is the most successful human genomic parasite affecting development and causing disease. It originated as a retrotransposon during early primate evolution of the gene encoding the signal recognition particle (SRP) RNA. We defined a minimal Alu RNA sufficient for effective retrotransposition and determined a high-resolution structure of its complex with the SRP9/14 proteins. The RNA adopts a compact, closed conformation that matches the envelope of the SRP Alu domain in the ribosomal translation elongation factor-binding site. Conserved structural elements in SRP RNAs support an ancient function of the closed conformation that predates SRP9/14. Structure-based mutagenesis shows that retrotransposition requires the closed conformation of the Alu ribonucleoprotein particle and is consistent with the recognition of stalled ribosomes. We propose that ribosome stalling is a common cause for the cis-preference of the mammalian L1 retrotransposon and for the efficiency of the Alu RNA in hijacking nascent L1 reverse transcriptase. Retrotransposition and Crystal Structure of an Alu RNP in the Ribosome-Stalling Conformation.,Ahl V, Keller H, Schmidt S, Weichenrieder O Mol Cell. 2015 Nov 11. pii: S1097-2765(15)00770-4. doi:, 10.1016/j.molcel.2015.10.003. PMID:26585389[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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