5h4p
From Proteopedia
Structural snapshot of cytoplasmic pre-60S ribosomal particles bound with Nmd3, Lsg1, Tif6 and Reh1
Structural highlights
Function[RL5_YEAST] Binds 5S RNA and is required for 60S subunit assembly. [REH1_YEAST] Pre-60S-associated cytoplasmic factor involved in the cytoplasmic maturation of the 60S subunit. May act redundantly with REI1 to directly promote a stabilizing structural rearrangement in cytoplasmic 60S subunit maturation independent on the REI1-specific ARX1 recycling.[1] [RL25_YEAST] This protein binds to a specific region on the 26S rRNA. [NMD3_YEAST] Acts as an adapter for the XPO1/CRM1-mediated export of the 60S ribosomal subunit. Unlikely to play a significant role in nonsense-mediated mRNA decay (NMD).[2] [RL4A_YEAST] Participates in the regulation of the accumulation of its own mRNA.[3] [RL11A_YEAST] Binds to 5S ribosomal RNA. [RL37A_YEAST] Binds to the 23S rRNA (By similarity). [IF6_YEAST] Binds to the 60S ribosomal subunit and prevents its association with the 40S ribosomal subunit to form the 80S initiation complex in the cytoplasm. Is also involved in ribosome biogenesis. Associates with pre-60S subunits in the nucleus and is involved in its nuclear export. Cytoplasmic release of TIF6 from 60S subunits and nuclear relocalization is promoted by the GTPase RIA1/EFL1 and by SDO1. Also required for pre-rRNA processing.[4] [5] [6] [7] [8] [9] Publication Abstract from PubMedA key step in ribosome biogenesis is the nuclear export of pre-ribosomal particles. Nmd3, a highly conserved protein in eukaryotes, is a specific adaptor required for the export of pre-60S particles. Here we used cryo-electron microscopy (cryo-EM) to characterize Saccharomyces cerevisiae pre-60S particles purified with epitope-tagged Nmd3. Our structural analysis indicates that these particles belong to a specific late stage of cytoplasmic pre-60S maturation in which ribosomal proteins uL16, uL10, uL11, eL40 and eL41 are deficient, but ribosome assembly factors Nmd3, Lsg1, Tif6 and Reh1 are present. Nmd3 and Lsg1 are located near the peptidyl-transferase center (PTC). In particular, Nmd3 recognizes the PTC in its near-mature conformation. In contrast, Reh1 is anchored to the exit of the polypeptide tunnel, with its C terminus inserted into the tunnel. These findings pinpoint a structural checkpoint role for Nmd3 in PTC assembly, and provide information about functional and mechanistic roles of these assembly factors in the maturation of the 60S ribosomal subunit. Structural snapshot of cytoplasmic pre-60S ribosomal particles bound by Nmd3, Lsg1, Tif6 and Reh1.,Ma C, Wu S, Li N, Chen Y, Yan K, Li Z, Zheng L, Lei J, Woolford JL Jr, Gao N Nat Struct Mol Biol. 2017 Mar;24(3):214-220. doi: 10.1038/nsmb.3364. Epub 2017, Jan 23. PMID:28112732[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Large Structures | Saccharomyces cerevisiae | Chen, Y | Gao, N | Lei, J | Li, N | Li, Z | Ma, C | Woolford, J L | Wu, S | Yan, K | Zheng, L | Assembly | Lsg1 | Nmd3 | Pre-60 | Ribosome
