9h52
Assembly intermediate of human mitochondrial ribosome small subunit in complex with NOA1, ERAL1, METTL17, MCAT and TFB1M (state N1)
Structural highlights
DiseaseERAL1_HUMAN Perrault syndrome type 2;Perrault syndrome type 1. The disease is caused by variants affecting the gene represented in this entry. FunctionERAL1_HUMAN Probable GTPase that plays a role in the mitochondrial ribosomal small subunit assembly. Specifically binds the 12S mitochondrial rRNA (12S mt-rRNA) to a 33 nucleotide section delineating the 3' terminal stem-loop region. May act as a chaperone that protects the 12S mt-rRNA on the 28S mitoribosomal subunit during ribosomal small subunit assembly.[1] [2] [3] Publication Abstract from PubMedAssembly of the mitochondrial ribosome (mitoribosome) is a crucial step in mitochondrial gene expression. This process facilitates mitochondrial translation, which produces essential subunits of the oxidative phosphorylation machinery-the cell's primary energy-producing machinery. Disruptions in mitoribosome assembly can lead to severe human diseases. Given its fundamental importance, detailed structural analysis of mitoribosome assembly pathways is essential for advancing our understanding of mitochondrial function in both health and disease. In this study, we characterize twelve distinct assembly states of the mitoribosomal small subunit (mtSSU) isolated from human cells. Our findings reveal the intricate details of the final maturation stages of the mtSSU platform, decoding center, and the 3'-end of 12S rRNA. This process is governed by coordinated actions of assembly factors that ensure precise, stepwise rRNA folding and the integration of mitoribosomal proteins into the developing subunit. Our approach identifies pseudouridine synthase PUS1 and initiation factor mtIF2 as assembly factors, expanding their known roles beyond mt-tRNA maturation and translation, respectively. In addition, the identified assembly intermediates provide insight into the modular nature of mtSSU biogenesis in mitochondria and further link late-stage assembly to the acquisition of translational competence. Pseudouridine synthase PUS1 and initiation factor mtIF2 are human mitoribosomal small subunit assembly factors.,Singh V, Shiriaev D, Bilalli L, Khawaja A, Rorbach J Nat Commun. 2026 Jun 24;17(1):5564. doi: 10.1038/s41467-026-74700-x. PMID:42342677[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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