Seroatlas · Human Serome Atlas

MRPS18C

Small ribosomal subunit protein bS18m

Also known as: CGI-134, FLJ11146, FLJ22967, MRPS18-1, RT18C_HUMAN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
Q9Y3D5
Gene
MRPS18C
Ensembl
ENSG00000163319
Chromosome
4
Canonical length
142 aa
Protein class
Predicted intracellular proteins, Ribosomal proteins

OverviewNCBI Gene

Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and help in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit. They have an estimated 75% protein to rRNA composition compared to prokaryotic ribosomes, where this ratio is reversed. Another difference between mammalian mitoribosomes and prokaryotic ribosomes is that the latter contain a 5S rRNA. Among different species, the proteins comprising the mitoribosome differ greatly in sequence, and sometimes in biochemical properties, which prevents easy recognition by sequence homology. This gene encodes a 28S subunit protein that belongs to the ribosomal protein S18P family. The encoded protein is one of three that has significant sequence similarity to bacterial S18 proteins. The primary sequences of the three human mitochondrial S18 proteins are no more closely related to each other than they are to the prokaryotic S18 proteins. Pseudogenes corresponding to this gene are found on chromosomes 8p, 12p, 15q, and 22q. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

142 residues, UniProt reviewed canonical sequence.

>Q9Y3D5|MRPS18C
     1  MAAVVAVCGG LGRKKLTHLV TAAVSLTHPG THTVLWRRGC SQQVSSNEDL PISMENPYKE
    61  PLKKCILCGK HVDYKNVQLL SQFVSPFTGC IYGRHITGLC GKKQKEITKA IKRAQIMGFM
   121  PVTYKDPAYL KDPKVCNIRY RE

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against MRPS18C can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Intracellular
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.52
Highest tissue expression
80 nTPM

Expression across tissuesHPA

Tissue

  • skeletal muscle: 80 nTPM
  • tongue: 50 nTPM
  • heart muscle: 44 nTPM
  • liver: 41 nTPM
  • esophagus: 33 nTPM
  • kidney: 33 nTPM

Single-cell type

  • esophageal apical cells: 302 nCPM
  • oocytes: 230 nCPM
  • megakaryocytes: 216 nCPM
  • hepatocytes: 200 nCPM
  • late primary spermatocytes: 193 nCPM
  • esophageal suprabasal cells: 182 nCPM

Immune cell

  • eosinophil: 197 nTPM
  • T-reg: 196 nTPM
  • memory B-cell: 176 nTPM
  • naive B-cell: 165 nTPM
  • plasmacytoid DC: 165 nTPM
  • myeloid DC: 143 nTPM

Brain region

  • hypothalamus: 17 nTPM
  • cerebellum: 17 nTPM
  • white matter: 17 nTPM
  • cerebral cortex: 15 nTPM
  • pons: 15 nTPM
  • spinal cord: 15 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
1.45
gnomAD pLI
0
gnomAD missense Z
0.43
DepMap mean gene effect
-0.27
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of MRPS18C in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads MRPS18C as an antibody target. Whether an autoantibody or antibody against MRPS18C could matter depends on whether native MRPS18C is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

MRPS18C is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label MRPS18C as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/MRPS18C. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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