Var 1 is associated with the small ribosomal subunit of mitochondrial ribosomes in yeast

1979 ◽  
Vol 174 (3) ◽  
pp. 339-342 ◽  
Author(s):  
Gert S. P. Groot ◽  
Thomas L. Mason ◽  
Nel Van Harten-Loosbroek
Keyword(s):  
Ribosomal Subunit ◽  
Small Ribosomal Subunit ◽  
Mitochondrial Ribosomes

scholarly journals METTL15 interacts with the assembly intermediate of murine mitochondrial small ribosomal subunit to form m4C840 12S rRNA residue

2020 ◽  
Vol 48 (14) ◽  
pp. 8022-8034 ◽  
Author(s):  
Ivan Laptev ◽  
Ekaterina Shvetsova ◽  
Sergey Levitskii ◽  
Marina Serebryakova ◽  
Maria Rubtsova ◽  
...  
Keyword(s):  
Protein Biosynthesis ◽  
Mitochondrial Protein ◽  
Ribosomal Subunit ◽  
12S Rrna ◽  
Small Ribosomal Subunit ◽  
Mitochondrial Ribosomes ◽  
Murine Cell Line ◽  
Assembly Factor ◽  
Mitochondrial 12S Rrna ◽  
Assembly Intermediate

Abstract Mammalian mitochondrial ribosomes contain a set of modified nucleotides, which is distinct from that of the cytosolic ribosomes. Nucleotide m4C840 of the murine mitochondrial 12S rRNA is equivalent to the dimethylated m4Cm1402 residue of Escherichia coli 16S rRNA. Here we demonstrate that mouse METTL15 protein is responsible for the formation of m4C residue of the 12S rRNA. Inactivation of Mettl15 gene in murine cell line perturbs the composition of mitochondrial protein biosynthesis machinery. Identification of METTL15 interaction partners revealed that the likely substrate for this RNA methyltransferase is an assembly intermediate of the mitochondrial small ribosomal subunit containing an assembly factor RBFA.

scholarly journals Structural basis of GTPase-mediated mitochondrial ribosome biogenesis and recycling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hauke S. Hillen ◽  
Elena Lavdovskaia ◽  
Franziska Nadler ◽  
Elisa Hanitsch ◽  
Andreas Linden ◽  
...  
Keyword(s):  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Ribosomal Subunit ◽  
Structural Basis ◽  
Peptidyl Transferase ◽  
Mitochondrial Ribosomes ◽  
Mitochondrial Ribosome ◽  
In Vitro Reconstitution

AbstractRibosome biogenesis requires auxiliary factors to promote folding and assembly of ribosomal proteins and RNA. Particularly, maturation of the peptidyl transferase center (PTC) is mediated by conserved GTPases, but the molecular basis is poorly understood. Here, we define the mechanism of GTPase-driven maturation of the human mitochondrial large ribosomal subunit (mtLSU) using endogenous complex purification, in vitro reconstitution and cryo-EM. Structures of transient native mtLSU assembly intermediates that accumulate in GTPBP6-deficient cells reveal how the biogenesis factors GTPBP5, MTERF4 and NSUN4 facilitate PTC folding. Addition of recombinant GTPBP6 reconstitutes late mtLSU biogenesis in vitro and shows that GTPBP6 triggers a molecular switch and progression to a near-mature PTC state. Additionally, cryo-EM analysis of GTPBP6-treated mature mitochondrial ribosomes reveals the structural basis for the dual-role of GTPBP6 in ribosome biogenesis and recycling. Together, these results provide a framework for understanding step-wise PTC folding as a critical conserved quality control checkpoint.

scholarly journals Structural Aspects of RbfA Action during Small Ribosomal Subunit Assembly

2007 ◽  
Vol 28 (3) ◽  
pp. 434-445 ◽  
Author(s):  
Partha P. Datta ◽  
Daniel N. Wilson ◽  
Masahito Kawazoe ◽  
Neil K. Swami ◽  
Tatsuya Kaminishi ◽  
...  
Keyword(s):  
Ribosomal Subunit ◽  
Small Ribosomal Subunit ◽  
Subunit Assembly ◽  
Structural Aspects

Reconstitution of a Minimal Small Ribosomal Subunit

1993 ◽  
pp. 719-726 ◽  
Author(s):  
Andrew Scheinman ◽  
Anna-Marie Aguinaldo ◽  
Agda M. Simpson ◽  
Marian Peris ◽  
Gary Shankweiler ◽  
...  
Keyword(s):  
Ribosomal Subunit ◽  
Small Ribosomal Subunit

scholarly journals The modifying enzyme Tsr3 establishes the hierarchy of Rio kinase activity in 40S ribosome assembly

2021 ◽  
Author(s):  
Haina Huang ◽  
Melissa Parker ◽  
Katrin Karbstein
Keyword(s):  
Quality Control ◽  
Binding Site ◽  
Ribosomal Rna ◽  
Ribosomal Proteins ◽  
Kinase Activity ◽  
Ribosomal Subunit ◽  
Ribosome Assembly ◽  
Small Ribosomal Subunit ◽  
Yeast Strains

AbstractRibosome assembly is an intricate process, which in eukaryotes is promoted by a large machinery comprised of over 200 assembly factors (AF) that enable the modification, folding, and processing of the ribosomal RNA (rRNA) and the binding of the 79 ribosomal proteins. While some early assembly steps occur via parallel pathways, the process overall is highly hierarchical, which allows for the integration of maturation steps with quality control processes that ensure only fully and correctly assembled subunits are released into the translating pool. How exactly this hierarchy is established, in particular given that there are many instances of RNA substrate “handover” from one highly related AF to another remains to be determined. Here we have investigated the role of Tsr3, which installs a universally conserved modification in the P-site of the small ribosomal subunit late in assembly. Our data demonstrate that Tsr3 separates the activities of the Rio kinases, Rio2 and Rio1, with whom it shares a binding site. By binding after Rio2 dissociation, Tsr3 prevents rebinding of Rio2, promoting forward assembly. After rRNA modification is complete, Tsr3 dissociates, thereby allowing for recruitment of Rio1. Inactive Tsr3 blocks Rio1, which can be rescued using mutants that bypass the requirement for Rio1 activity. Finally, yeast strains lacking Tsr3 randomize the binding of the two kinases, leading to the release of immature ribosomes into the translating pool. These data demonstrate a role for Tsr3 and its modification activity in establishing a hierarchy for the function of the Rio kinases.

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