APOC4
Apolipoprotein C-IV
Also known as: APOC4_HUMAN
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- P55056
- Gene
- APOC4
- Ensembl
- ENSG00000267467
- Chromosome
- 19
- Canonical length
- 127 aa
- Protein class
- Plasma proteins, Predicted secreted proteins
- Secretome location
- Secreted to blood
OverviewNCBI Gene
This gene encodes a lipid-binding protein belonging to the apolipoprotein gene family. The protein is thought to play a role in lipid metabolism. Polymorphisms in this gene may influence circulating lipid levels and may be associated with coronary artery disease risk. This gene is present in a cluster with other related apolipoprotein genes on chromosome 19. Naturally occurring read-through transcription exists between this gene and the neighboring downstream apolipoprotein C-II (APOC2) gene. [provided by RefSeq, Mar 2011]
Canonical amino-acid sequenceUniProt
127 residues, UniProt reviewed canonical sequence.
>P55056|APOC4
1 MSLLRNRLQA LPALCLCVLV LACIGACQPE AQEGTLSPPP KLKMSRWSLV RGRMKELLET
61 VVNRTRDGWQ WFWSPSTFRG FMQTYYDDHL RDLGPLTKAW FLESKDSLLK KTHSLCPRLV
121 CGDKDQGLocalizationUniProt · AlphaFold · HPA
Whether an antibody against APOC4 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)
- 0.54
- Highest tissue expression
- 586 nTPM
Expression across tissuesHPA
Tissue
- liver: 586 nTPM
- testis: 1.1 nTPM
- epididymis: 0.6 nTPM
- bone marrow: 0.4 nTPM
- endometrium: 0.4 nTPM
- gallbladder: 0.3 nTPM
Single-cell type
- hepatocytes: 22 nCPM
- microglia: 2.9 nCPM
- astrocytes: 0.9 nCPM
- bergmann glia: 0.4 nCPM
- brain excitatory neurons: 0.1 nCPM
- brain inhibitory neurons: 0.1 nCPM
Immune cell
- neutrophil: 0.7 nTPM
- basophil: 0.4 nTPM
- intermediate monocyte: 0.4 nTPM
- plasmacytoid DC: 0.4 nTPM
- classical monocyte: 0.1 nTPM
- eosinophil: 0.1 nTPM
Brain region
- white matter: 4.7 nTPM
- cerebral cortex: 3.9 nTPM
- cerebellum: 3.7 nTPM
- amygdala: 3.5 nTPM
- basal ganglia: 3.4 nTPM
- hippocampal formation: 3.2 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)
- 1.94
- gnomAD pLI
- 0
- gnomAD missense Z
- 0.25
- DepMap mean gene effect
- 0.1
- DepMap dependency class
- selective
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
- Apolipoprotein C-IV
- Apolipoprotein C4
KeywordsUniProt
Antibody and autoantibody relevanceSeroatlas analysis
Seroatlas reads APOC4 as an antibody target. Whether an autoantibody or antibody against APOC4 could matter depends on whether native APOC4 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
APOC4 is annotated as secreted, so native APOC4 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 APOC4 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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