7qgg
From Proteopedia
Neuronal RNA granules are ribosome complexes stalled at the pre-translocation state
Structural highlights
FunctionRS4X_RAT Component of the small ribosomal subunit. The ribosome is a large ribonucleoprotein complex responsible for the synthesis of proteins in the cell. Part of the small subunit (SSU) processome, first precursor of the small eukaryotic ribosomal subunit. During the assembly of the SSU processome in the nucleolus, many ribosome biogenesis factors, an RNA chaperone and ribosomal proteins associate with the nascent pre-rRNA and work in concert to generate RNA folding, modifications, rearrangements and cleavage as well as targeted degradation of pre-ribosomal RNA by the RNA exosome.[UniProtKB:P62701] Publication Abstract from PubMedThe polarized cell morphology of neurons dictates many neuronal processes, including the axodendridic transport of specific mRNAs and subsequent translation. mRNAs together with ribosomes and RNA-binding proteins form RNA granules that are targeted to axodendrites for localized translation in neurons. It has been established that localized protein synthesis in neurons is essential for long-term memory formation, synaptic plasticity, and neurodegeneration. We have used proteomics and electron microscopy to characterize neuronal RNA granules (nRNAg) isolated from rat brain tissues or human neuroblastoma. We show that ribosome-containing RNA granules are morula-like structures when visualized by electron microscopy. Crosslinking-coupled mass-spectrometry identified a potential G3BP2 binding site on the ribosome near the eIF3d-binding site on the 40S ribosomal subunit. We used cryo-EM to resolve the structure of the ribosome-component of nRNAg. The cryo-EM reveals that predominant particles in nRNAg are 80S ribosomes, resembling the pre-translocation state where tRNA's are in the hybrid A/P and P/E site. We also describe a new kind of principal motion of the ribosome, which we call the rocking motion. Neuronal RNA granules are ribosome complexes stalled at the pre-translocation state.,Kipper K, Mansour A, Pulk A J Mol Biol. 2022 Oct 30;434(20):167801. doi: 10.1016/j.jmb.2022.167801. Epub 2022 , Aug 28. PMID:36038000[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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