Seroatlas · Human Serome Atlas

MMAA

Methylmalonic aciduria type A protein, mitochondrial

Also known as: cblA, MMAA_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q8IVH4
Gene: MMAA
Ensembl: ENSG00000151611
Chromosome: 4
Canonical length: 418 aa
Protein class: Disease related genes, Human disease related genes, Metabolic proteins, Predicted intracellular proteins
Subcellular location: Cytosol
Quaternary structure: Homodimer

OverviewNCBI Gene

The protein encoded by this gene is involved in the translocation of cobalamin into the mitochondrion, where it is used in the final steps of adenosylcobalamin synthesis. Adenosylcobalamin is a coenzyme required for the activity of methylmalonyl-CoA mutase. Defects in this gene are a cause of methylmalonic aciduria. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

418 residues, UniProt reviewed canonical sequence.

>Q8IVH4|MMAA
     1  MPMLLPHPHQ HFLKGLLRAP FRCYHFIFHS STHLGSGIPC AQPFNSLGLH CTKWMLLSDG
    61  LKRKLCVQTT LKDHTEGLSD KEQRFVDKLY TGLIQGQRAC LAEAITLVES THSRKKELAQ
   121  VLLQKVLLYH REQEQSNKGK PLAFRVGLSG PPGAGKSTFI EYFGKMLTER GHKLSVLAVD
   181  PSSCTSGGSL LGDKTRMTEL SRDMNAYIRP SPTRGTLGGV TRTTNEAILL CEGAGYDIIL
   241  IETVGVGQSE FAVADMVDMF VLLLPPAGGD ELQGIKRGII EMADLVAVTK SDGDLIVPAR
   301  RIQAEYVSAL KLLRKRSQVW KPKVIRISAR SGEGISEMWD KMKDFQDLML ASGELTAKRR
   361  KQQKVWMWNL IQESVLEHFR THPTVREQIP LLEQKVLIGA LSPGLAADFL LKAFKSRD

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against MMAA 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): 0.36
Highest tissue expression: 23 nTPM

Expression across tissuesHPA

Tissue

liver: 23 nTPM
duodenum: 7 nTPM
kidney: 6.8 nTPM
small intestine: 5.9 nTPM
tongue: 5.6 nTPM
colon: 5.5 nTPM

Single-cell type

early spermatids: 300 nCPM
late primary spermatocytes: 48 nCPM
hepatocytes: 41 nCPM
cardiomyocytes: 33 nCPM
late spermatids: 31 nCPM
pancreatic acinar cells: 23 nCPM

Immune cell

non-classical monocyte: 7.4 nTPM
intermediate monocyte: 6.1 nTPM
memory CD4 T-cell: 5.3 nTPM
naive CD8 T-cell: 5.3 nTPM
T-reg: 5.2 nTPM
NK-cell: 4.8 nTPM

Brain region

cerebellum: 8.8 nTPM
cerebral cortex: 7.9 nTPM
basal ganglia: 7.1 nTPM
midbrain: 6.6 nTPM
white matter: 6.4 nTPM
hypothalamus: 6.2 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about MMAA.

Disease | AllUniProt

Conditions MMAA is implicated in, by any mechanism.

Methylmalonic aciduria, cblA type (MACA) MIM:251100

Disease | GeneticClinVar

141 pathogenic / likely-pathogenic of 658 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

Methylmalonic aciduria, cblA type
Methylmalonic acidemia
MMAA-related disorder
See cases
Methylmalonic aciduria of the cblA complementation type

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): 1.29
gnomAD pLI: 0
gnomAD missense Z: 0.33
DepMap mean gene effect: 0.01
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% 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

P-loop containing nucleoside triphosphate hydrolase
SIMIBI class G3E GTPase, ArgK/MeaB
Methylmalonyl Co-A mutase-associated GTPase MeaB

KeywordsUniProt

InteractionsUniProt · HPA

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

MMUT

Antibody and autoantibody relevanceSeroatlas analysis

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

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

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