9p7x
In situ human A-P-Z state 80S ribosome
Structural highlights
FunctionRSSA_HUMAN Required for the assembly and/or stability of the 40S ribosomal subunit. Required for the processing of the 20S rRNA-precursor to mature 18S rRNA in a late step of the maturation of 40S ribosomal subunits. Also functions as a cell surface receptor for laminin. Plays a role in cell adhesion to the basement membrane and in the consequent activation of signaling transduction pathways. May play a role in cell fate determination and tissue morphogenesis. Acts as a PPP1R16B-dependent substrate of PPP1CA. Also acts as a receptor for several other ligands, including the pathogenic prion protein, viruses, and bacteria.[1] [2] [3] Publication Abstract from PubMedComprehensive in situ structures of macromolecules can transform our understanding of biology and advance human health. Here, we map protein synthesis inside human cells in detail by combining automated cryo-focused ion beam (FIB) milling and in situ single-particle cryo electron microscopy (cryo-EM). With this in situ cryo-EM approach, we resolved a 2.2 A consensus structure of the human 80S ribosome and unveiled 23 functional states, nearly all better than 3 A resolution. Compared to in vitro studies, we observed variations in ribosome structures, distinct environments of ion and polyamine binding, and associated proteins such as EDF1 and NACbeta that are typically not enriched with purified ribosomes. We also detected additional peptide-related density features on the ribosome and visualized ribosome-ribosome interactions in helical polysomes. Finally, high-resolution structures from cells treated with homoharringtonine and cycloheximide revealed a distinct translational landscape and a spermidine that interacts with cycloheximide at the E site, one of the numerous polyamines that also bind native ribosomes. These results underscore the value of high-resolution in situ studies in the native environment. Visualizing the translation landscape in human cells at high resolution.,Zheng W, Zhang Y, Wang J, Wang S, Chai P, Bailey EJ, Zhu C, Guo W, Devarkar SC, Wu S, Lin J, Zhang K, Liu J, Lomakin IB, Xiong Y Nat Commun. 2025 Nov 28;16(1):10757. doi: 10.1038/s41467-025-65795-9. PMID:41315256[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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