MRPL24

Model summary

A core architectural protein of the human mitochondrial large ribosomal subunit that stabilizes rRNA and neighboring components to sustain mitochondrial translation. Its β-barrel core binds RNA and assembly partners, creating a rigid platform that supports elongation and couples ribosome function to the inner membrane where nascent hydrophobic chains are inserted and utilized.

Predicted Gene Ontology terms

1. 01

   I begin with the InterPro architecture.

   The sequence is globally classified as IPR003256 (Large ribosomal subunit protein uL24 family, residues 1–216), establishing identity as a universal large-subunit ribosomal protein that builds the core of the ribosome’s functional center. The central body of the protein is annotated by IPR014722 (Large ribosomal subunit protein uL24, domain 2, residues 47–153) and IPR057264 (uL24 C-terminal domain, residues 91–154), indicating a bipartite core that anchors to rRNA and neighboring ribosomal proteins. Within this core, IPR008991 (Translation protein SH3-like domain superfamily, residues 50–153) and IPR005824 (KOW domain, residues 55–88) define a β-barrel SH3-like fold that specializes in nucleic-acid and protein interactions. The KOW module is further specified by IPR041988 (uL24 KOW domain, residues 59–122) and the conserved motif IPR005825 (uL24 conserved site, residues 59–76), together forming an RNA/protein-binding platform that stabilizes ribonucleoprotein assemblies. This ordered arrangement—N-terminal family-defining scaffold feeding into a central SH3-like/KOW β-barrel and a structured C-terminal domain—creates a rigid yet adaptable surface that binds rRNA and recruits partner proteins.

2. 02

   This architecture dictates molecular function.

   The uL24 family scaffold and SH3-like/KOW core generate a stable structural element of the ribosome, satisfying GO:0003735 structural constituent of ribosome. The KOW β-barrel and conserved site provide direct nucleic-acid affinity, supporting GO:0003723 RNA binding. The extended β-barrel and adjacent surfaces mediate multivalent contacts with neighboring ribosomal proteins and assembly factors, accounting for GO:0005515 protein binding.

3. 03

   From these molecular activities, the biological process follows.

   By furnishing a rigid platform that binds rRNA and organizes neighboring subunits, this protein drives peptide synthesis in mitochondria, aligning with GO:0006412 translation. Its role is not catalytic but architectural—positioning rRNA helices and coordinating assembly to sustain elongation.

4. 04

   Cellular localization emerges from the ribosomal identity and mitochondrial specialization of the uL24 family.

   The protein integrates into the mitochondrial large ribosomal subunit, matching GO:0005762 mitochondrial large ribosomal subunit. Human mitoribosomes operate on the matrix side but are tethered to the mitochondrial inner membrane to couple translation with membrane insertion of nascent chains; thus the assembly resides functionally at GO:0005743 mitochondrial inner membrane. This spatial arrangement ensures co-translational targeting of hydrophobic respiratory chain components.

5. 05

   Mechanistically, the KOW/SH3-like core binds and shapes LSU rRNA near the functional center, while the C-terminal domain buttresses inter-subunit contacts and assembly intermediates.

   This causes stable ribonucleoprotein architecture that supports elongation and coordinates with membrane-proximal translation. Likely interaction partners include neighboring LSU proteins that contour the functional center and exit tunnel (e.g., uL23m and uL29m), as well as assembly and mRNA-handling factors that dock via β-barrel-mediated interfaces. Together, these interactions position the mitoribosome at the inner membrane to synthesize and deliver hydrophobic polypeptides efficiently.