PUBLICATION

A homozygous MRPL24 mutation causes a complex movement disorder and affects the mitoribosome assembly

Authors
Nottia, M.D., Marchese, M., Verrigni, D., Mutti, C., Torraco, A., Oliva, R., Fernandez-Vizarra, E., Morani, F., Trani, G., Rizza, T., Ghezzi, D., Ardissone, A., Nesti, C., Vasco, G., Zeviani, M., Minczuk, M., Bertini, E., Santorelli, F.M., Carrozzo, R.
ID
ZDB-PUB-200429-17
Date
2020
Source
Neurobiology of disease   141: 104880 (Journal)
Registered Authors
Keywords
MRPL24, Mitochondrial disorders, Mitochondrial protein synthesis, Mitoribosomes, Molecular modeling, Movement disorder, Protein interactions, Zebrafish
MeSH Terms
  • Animals
  • Cerebellum/pathology
  • Female
  • Humans
  • Infant
  • Leviviridae
  • Male
  • Mitochondrial Proteins/genetics*
  • Movement Disorders/genetics*
  • Movement Disorders/pathology
  • Quadriceps Muscle/pathology
  • Ribosomal Proteins/genetics*
  • Zebrafish
PubMed
32344152 Full text @ Neurobiol. Dis.
Abstract
Mitochondrial ribosomal protein large 24 (MRPL24) is 1 of the 82 protein components of mitochondrial ribosomes, playing an essential role in the mitochondrial translation process. We report here on a baby girl with cerebellar atrophy, choreoathetosis of limbs and face, intellectual disability and a combined defect of complexes I and IV in muscle biopsy, caused by a homozygous missense mutation identified in MRPL24. The variant predicts a Leu91Pro substitution at an evolutionarily conserved site. Using human mutant cells and the zebrafish model, we demonstrated the pathological role of the identified variant. In fact, in fibroblasts we observed a significant reduction of MRPL24 protein and of mitochondrial respiratory chain complex I and IV subunits, as well a markedly reduced synthesis of the mtDNA-encoded peptides. In zebrafish we demonstrated that the orthologue gene is expressed in metabolically active tissues, and that gene knockdown induced locomotion impairment, structural defects and low ATP production. The motor phenotype was complemented by human WT but not mutant cRNA. Moreover, sucrose density gradient fractionation showed perturbed assembly of large subunit mitoribosomal proteins, suggesting that the mutation leads to a conformational change in MRPL24, which is expected to cause an aberrant interaction of the protein with other components of the 39S mitoribosomal subunit.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping