Seroatlas · Human Serome Atlas

MCUB

Calcium uniporter regulatory subunit MCUb, mitochondrial

Also known as: CCDC109B, FLJ20647, MCUB_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q9NWR8
Gene: MCUB
Ensembl: ENSG00000005059
Chromosome: 4
Canonical length: 336 aa
Protein class: Predicted membrane proteins, Transporters
Subcellular location: Mitochondria,Cytosol
Quaternary structure: Homooligomer

OverviewNCBI Gene

Enables calcium channel inhibitor activity. Involved in negative regulation of calcium import into the mitochondrion. Located in cytosol and mitochondrial inner membrane. Part of uniplex complex. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

336 residues, UniProt reviewed canonical sequence.

>Q9NWR8|MCUB
     1  MLQRGLWPWR TRLLPTPGTW RPARPWPLPP PPQVLRVKLC GNVKYYQSHH YSTVVPPDEI
    61  TVIYRHGLPL VTLTLPSRKE RCQFVVKPML STVGSFLQDL QNEDKGIKTA AIFTADGNMI
   121  SASTLMDILL MNDFKLVINK IAYDVQCPKR EKPSNEHTAE MEHMKSLVHR LFTILHLEES
   181  QKKREHHLLE KIDHLKEQLQ PLEQVKAGIE AHSEAKTSGL LWAGLALLSI QGGALAWLTW
   241  WVYSWDIMEP VTYFITFANS MVFFAYFIVT RQDYTYSAVK SRQFLQFFHK KSKQQHFDVQ
   301  QYNKLKEDLA KAKESLKQAR HSLCLQMQVE ELNEKN

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against MCUB 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: Other membrane
Secreted: No
Transmembrane segments: 2
Mean surface accessibility (rSASA): 0.44
Highest tissue expression: 30 nTPM

Expression across tissuesHPA

Tissue

lymph node: 30 nTPM
thymus: 29 nTPM
tonsil: 24 nTPM
appendix: 17 nTPM
spleen: 13 nTPM
heart muscle: 10 nTPM

Single-cell type

cytotrophoblasts: 196 nCPM
epicardial cells: 191 nCPM
t-cells: 170 nCPM
retinal bipolar cells: 157 nCPM
monocytes: 155 nCPM
hofbauer cells: 153 nCPM

Immune cell

naive CD4 T-cell: 115 nTPM
total PBMC: 92 nTPM
memory CD4 T-cell: 79 nTPM
T-reg: 75 nTPM
naive CD8 T-cell: 66 nTPM
NK-cell: 65 nTPM

Brain region

thalamus: 8.2 nTPM
hypothalamus: 7.2 nTPM
white matter: 7.2 nTPM
medulla oblongata: 6.5 nTPM
spinal cord: 5.2 nTPM
choroid plexus: 4.6 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): 1.35
gnomAD pLI: 0
DepMap mean gene effect: 0.11
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

calcium channel inhibitor activity

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

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

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

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