Seroatlas · Human Serome Atlas

MRPL21

Large ribosomal subunit protein bL21m

Also known as: RM21_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q7Z2W9
Gene: MRPL21
Ensembl: ENSG00000197345
Chromosome: 11
Canonical length: 205 aa
Protein class: Predicted intracellular proteins, Ribosomal proteins
Subcellular location: Nucleoplasm,Mitochondria

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 39S subunit protein. Multiple transcript variants encoding different isoforms were identified through sequence analysis although some may be subject to nonsense-mediated decay (NMD). [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

205 residues, UniProt reviewed canonical sequence.

>Q7Z2W9|MRPL21
     1  MAASSLTVTL GRLASACSHS ILRPSGPGAA SLWSASRRFN SQSTSYLPGY VPKTSLSSPP
    61  WPEVVLPDPV EETRHHAEVV KKVNEMIVTG QYGRLFAVVH FASRQWKVTS EDLILIGNEL
   121  DLACGERIRL EKVLLVGADN FTLLGKPLLG KDLVRVEATV IEKTESWPRI IMRFRKRKNF
   181  KKKRIVTTPQ TVLRINSIEI APCLL

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against MRPL21 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): 0.48
Highest tissue expression: 123 nTPM

Expression across tissuesHPA

Tissue

skeletal muscle: 123 nTPM
heart muscle: 115 nTPM
tongue: 102 nTPM
salivary gland: 94 nTPM
kidney: 74 nTPM
cerebral cortex: 74 nTPM

Single-cell type

late spermatids: 288 nCPM
gastric progenitor cells: 237 nCPM
esophageal basal cells: 219 nCPM
esophageal suprabasal cells: 201 nCPM
late primary spermatocytes: 200 nCPM
early spermatids: 168 nCPM

Immune cell

memory B-cell: 163 nTPM
myeloid DC: 125 nTPM
intermediate monocyte: 123 nTPM
non-classical monocyte: 115 nTPM
total PBMC: 114 nTPM
T-reg: 114 nTPM

Brain region

cerebellum: 46 nTPM
hypothalamus: 40 nTPM
medulla oblongata: 40 nTPM
pons: 39 nTPM
cerebral cortex: 36 nTPM
choroid plexus: 36 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): 1.87
gnomAD pLI: 0
gnomAD missense Z: 0.27
DepMap mean gene effect: -0.68
DepMap dependency class: common

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 8% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

mitochondrial translation

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

Large ribosomal subunit protein bL21
Large ribosomal subunit protein bL21-like
Large ribosomal subunit protein bL21-like superfamily
Ribosomal prokaryotic L21 protein

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of MRPL21 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 MRPL21 as an antibody target. Whether an autoantibody or antibody against MRPL21 could matter depends on whether native MRPL21 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

MRPL21 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 MRPL21 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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