Seroatlas · Human Serome Atlas

APOM

Apolipoprotein M

Also known as: Apo-M, APOM_HUMAN, G3a, NG20

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

Protein identityUniProt · HPA

UniProt accession: O95445
Gene: APOM
Ensembl: ENSG00000204444
Chromosome: 6
Canonical length: 188 aa
Protein class: Plasma proteins, Predicted intracellular proteins, Predicted secreted proteins
Subcellular location: Golgi apparatus
Secretome location: Secreted to blood

OverviewNCBI Gene

The protein encoded by this gene is an apolipoprotein and member of the lipocalin protein family. It is found associated with high density lipoproteins and to a lesser extent with low density lipoproteins and triglyceride-rich lipoproteins. The encoded protein is secreted through the plasma membrane but remains membrane-bound, where it is involved in lipid transport. Alternate splicing results in both coding and non-coding variants of this gene. [provided by RefSeq, Jan 2012]

Canonical amino-acid sequenceUniProt

188 residues, UniProt reviewed canonical sequence.

>O95445|APOM
     1  MFHQIWAALL YFYGIILNSI YQCPEHSQLT TLGVDGKEFP EVHLGQWYFI AGAAPTKEEL
    61  ATFDPVDNIV FNMAAGSAPM QLHLRATIRM KDGLCVPRKW IYHLTEGSTD LRTEGRPDMK
   121  TELFSSSCPG GIMLNETGQG YQRFLLYNRS PHPPEKCVEE FKSLTSCLDS KAFLLTPRNQ
   181  EACELSNN

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against APOM 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: Secreted
Secreted: Yes
Transmembrane segments: 0
Mean surface accessibility (rSASA): 0.32
Highest tissue expression: 449 nTPM

Expression across tissuesHPA

Tissue

liver: 449 nTPM
kidney: 111 nTPM
testis: 15 nTPM
small intestine: 9.6 nTPM
skeletal muscle: 7 nTPM
midbrain: 6.8 nTPM

Single-cell type

hepatocytes: 694 nCPM
late primary spermatocytes: 96 nCPM
enterocytes: 68 nCPM
early spermatids: 53 nCPM
late spermatids: 44 nCPM
epididymal efferent duct absorptive cells: 31 nCPM

Immune cell

basophil: 3 nTPM
memory B-cell: 1.1 nTPM
non-classical monocyte: 0.7 nTPM
T-reg: 0.7 nTPM
classical monocyte: 0.6 nTPM
eosinophil: 0.6 nTPM

Brain region

cerebellum: 1.4 nTPM
medulla oblongata: 0.9 nTPM
white matter: 0.9 nTPM
cerebral cortex: 0.8 nTPM
hypothalamus: 0.8 nTPM
midbrain: 0.8 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): 1.19
gnomAD pLI: 0
gnomAD missense Z: 0.94
DepMap mean gene effect: -0.04
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

Calycin
Apolipoprotein M
ApoM domain

KeywordsUniProt

InteractionsUniProt · HPA

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

LRP2

Antibody and autoantibody relevanceSeroatlas analysis

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

APOM is annotated as secreted, so native APOM circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

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

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