S18 family of mitochondrial ribosomal proteins: evolutionary history and Gly132 polymorphism in colon carcinoma

Oncotarget. 2016 Aug 23;7(34):55649-55662. doi: 10.18632/oncotarget.10957.


S18 family of mitochondrial ribosomal proteins (MRPS18, S18) consists of three members, S18-1 to -3. Earlier, we found that overexpression of S18-2 protein resulted in immortalization and eventual transformation of primary rat fibroblasts. The S18-1 and -3 have not exhibited such abilities. To understand the differences in protein properties, the evolutionary history of S18 family was analyzed. The S18-3, followed by S18-1 and S18-2 emerged as a result of ancient gene duplication in the root of eukaryotic species tree, followed by two metazoan-specific gene duplications. However, the most conserved metazoan S18 homolog is the S18-1; it shares the most sequence similarity with S18 proteins of bacteria and of other eukaryotic clades. Evolutionarily conserved residues of S18 proteins were analyzed in various cancers. S18-2 is mutated at a higher rate, compared with S18-1 and -3 proteins. Moreover, the evolutionarily conserved residue, Gly132 of S18-2, shows genetic polymorphism in colon adenocarcinomas that was confirmed by direct DNA sequencing.Concluding, S18 family represents the yet unexplored important mitochondrial ribosomal proteins.

Keywords: MRPS18 family; evolutionary trace analysis; genetic polymorphism; mitochondrial ribosomal proteins; phylogenetic analysis.

MeSH terms

  • Colonic Neoplasms / genetics*
  • Evolution, Molecular*
  • Humans
  • Mitochondrial Proteins / genetics*
  • Mutation
  • Phylogeny
  • Polymorphism, Genetic*
  • Ribosomal Proteins / genetics*


  • MRPS18C protein, human
  • Mitochondrial Proteins
  • Ribosomal Proteins
  • ribosomal protein S18