Related Experiment Video

Updated: Jun 21, 2025

Rapid Isolation of the Mitoribosome from HEK Cells
09:33

Rapid Isolation of the Mitoribosome from HEK Cells

Published on: October 4, 2018

11.0K

GTPBP8 plays a role in mitoribosome formation in human mitochondria

Miriam Cipullo1, Genís Valentín Gesé2, Shreekara Gopalakrishna1

  • 1Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, 17165, Sweden.

Nature Communications
|July 5, 2024
PubMed

Insights

GTP-binding protein 8 (GTPBP8) is crucial for human mitochondrial ribosome assembly. Its absence impairs mitochondrial translation and oxidative phosphorylation by halting large subunit maturation.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Mitochondrial gene expression is essential for cellular energy production.
  • Mitoribosome biogenesis requires numerous assembly factors, including GTP-binding proteins (GTPBPs).
  • Bacterial EngB, a GTPBP, is vital for large ribosomal subunit assembly.

Purpose of the Study:

  • To investigate the function of GTPBP8, the human homolog of bacterial EngB.
  • To elucidate the role of GTPBP8 in mitochondrial gene expression and mitoribosome biogenesis.

Main Methods:

  • Generated GTPBP8 knock-out cells.
  • Performed structural analysis of mitoribosomes.
  • Utilized fPAR-CLIP analysis to identify RNA interactions.

Main Results:

  • GTPBP8 ablation inhibited mitochondrial translation and impaired oxidative phosphorylation.
  • Knock-out cells accumulated mitoribosomal large subunit assembly intermediates.
  • GTPBP8 binds specifically to the 16S rRNA of the mitochondrial ribosome large subunit.

Conclusions:

  • GTPBP8 is essential for mitochondrial large subunit maturation.
  • GTPBP8 functions as an RNA-binding protein within the mitochondrial gene expression machinery.
  • This study identifies GTPBP8 as a key factor in maintaining mitochondrial function.

More Related Videos

Author Spotlight: Advancing Techniques and Discoveries in Protein Synthesis and Assembly Through Innovative Mitochondrial Research09:53

Author Spotlight: Advancing Techniques and Discoveries in Protein Synthesis and Assembly Through Innovative Mitochondrial Research

Published on: June 7, 2024

933
Reconstitution of Msp1 Extraction Activity with Fully Purified Components05:52

Reconstitution of Msp1 Extraction Activity with Fully Purified Components

Published on: August 10, 2021

2.4K

Related Concept Videos

Mitochondrial Precursor Proteins01:39

Mitochondrial Precursor Proteins

Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70  chaperones are targetted to TOM20-TOM22 receptor complexes.
Most of the mitochondrial...
2.6K
Translocation of Proteins into the Mitochondria01:19

Translocation of Proteins into the Mitochondria

Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
3.1K
Porin Insertion in the Outer Mitochondrial Membrane01:12

Porin Insertion in the Outer Mitochondrial Membrane

Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
2.9K
Mitochondrial Protein Sorting01:39

Mitochondrial Protein Sorting

Mitochondria are double-membrane organelles of the eukaryotes involved in cellular metabolism, signaling, ATP synthesis, and programmed cell death.  Each of these processes requires specific proteins and enzymes that must be correctly sorted to the right mitochondrial subcompartment for the proper functioning of the organelle.
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
4.3K
Structure of Porins01:21

Structure of Porins

Mitochondria, chloroplasts, and gram-negative bacteria have transmembrane, beta-barrel proteins called porins to mediate the free diffusion of ions and metabolites across the membrane. Mitochondrial porin precursors contain conserved amino acid sequences called beta signals at their C-terminal. Beta signals have a  motif of PoXGXXHyXHy (Po-Polar, X-Any amino acid, G-Glycine, Hy-LargeHydrophobic), which are crucial for precursor recognition to initiate precursor assembly. Beta-barrel...
2.9K
Protein Transport into the Inner Mitochondrial Membrane01:34

Protein Transport into the Inner Mitochondrial Membrane

Nuclear encoded mitochondrial precursors are imported to the inner membrane in a multistep process involving two separate translocons, TIM22 and TIM23. TIM23 is a cation-selective pore that remains closed by the N terminal segment of the protein. Negative charges on the TIM23 act as a receptor for the incoming precursor, pulling the positively charged matrix-targeting sequence for peptide insertion and translocation.
Transport of mitochondrial precursors across the TIM23 channel is driven by...
3.7K