APOA2
Apolipoprotein A-II
Also known as: APOA2_HUMAN
Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene
Protein identityUniProt · HPA
- UniProt accession
- P02652
- Gene
- APOA2
- Ensembl
- ENSG00000158874
- Chromosome
- 1
- Canonical length
- 100 aa
- Protein class
- Cancer-related genes, Candidate cardiovascular disease genes, Human disease related genes, Metabolic proteins, Plasma proteins, Predicted intracellular proteins, Predicted secreted proteins, Transporters
- Secretome location
- Secreted to blood
- Quaternary structure
- Homodimer
OverviewNCBI Gene
This gene encodes apolipoprotein (apo-) A-II, which is the second most abundant protein of the high density lipoprotein particles. The protein is found in plasma as a monomer, homodimer, or heterodimer with apolipoprotein D. Defects in this gene may result in apolipoprotein A-II deficiency or hypercholesterolemia. [provided by RefSeq, Jul 2008]
Canonical amino-acid sequenceUniProt
100 residues, UniProt reviewed canonical sequence.
>P02652|APOA2
1 MKLLAATVLL LTICSLEGAL VRRQAKEPCV ESLVSQYFQT VTDYGKDLME KVKSPELQAE
61 AKSYFEKSKE QLTPLIKKAG TELVNFLSYF VELGTQPATQLocalizationUniProt · AlphaFold · HPA
Whether an antibody against APOA2 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)
- 0.52
- Highest tissue expression
- 33,507 nTPM
Expression across tissuesHPA
Tissue
- liver: 33,507 nTPM
- bone marrow: 25 nTPM
- kidney: 8.8 nTPM
- spleen: 6.5 nTPM
- adipose tissue: 3.9 nTPM
- pancreas: 2.1 nTPM
Single-cell type
- hepatocytes: 52,172 nCPM
- cholangiocytes: 316 nCPM
- hepatic stellate cells: 278 nCPM
- kupffer cells: 100 nCPM
- late spermatids: 14 nCPM
- b-cells: 12 nCPM
Immune cell
- neutrophil: 0.7 nTPM
- intermediate monocyte: 0.4 nTPM
- classical monocyte: 0.2 nTPM
- myeloid DC: 0.2 nTPM
- plasmacytoid DC: 0.2 nTPM
- non-classical monocyte: 0.1 nTPM
Brain region
- cerebral cortex: 2.6 nTPM
- medulla oblongata: 1.9 nTPM
- pons: 1.9 nTPM
- white matter: 1.9 nTPM
- choroid plexus: 1.8 nTPM
- hypothalamus: 1.5 nTPM
DiseaseUniProt · ClinVar · IEDB · PubMed
Four sources answering four different questions about APOA2.
Disease | GeneticClinVar
3 pathogenic / likely-pathogenic of 35 ClinVar records.
Conditions with pathogenic or likely-pathogenic variants.
- APOLIPOPROTEIN A-II DEFICIENCY
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)
- 1.72
- gnomAD pLI
- 0.04
- gnomAD missense Z
- 0.31
- DepMap mean gene effect
- -0.04
- 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
- cellular response to lipoprotein particle stimulus
- cholesterol efflux
- cholesterol homeostasis
- cholesterol metabolic process
- cholesterol transport
- diacylglycerol catabolic process
- high-density lipoprotein particle assembly
- high-density lipoprotein particle clearance
- high-density lipoprotein particle remodeling
- lipoprotein metabolic process
- low-density lipoprotein particle remodeling
- negative regulation of cholesterol import
- negative regulation of cholesterol transport
- negative regulation of cytokine production involved in immune response
- negative regulation of lipid catabolic process
- negative regulation of very-low-density lipoprotein particle remodeling
- peptidyl-methionine modification
- phosphatidylcholine biosynthetic process
- phospholipid catabolic process
- phospholipid efflux
- positive regulation of interleukin-8 production
- positive regulation of lipid catabolic process
- positive regulation of phagocytosis
- protein oxidation
- protein stabilization
- regulation of intestinal cholesterol absorption
- regulation of protein stability
- response to glucose
- reverse cholesterol transport
- triglyceride metabolic process
- triglyceride-rich lipoprotein particle remodeling
Molecular functions
- apolipoprotein receptor binding
- cholesterol binding
- enzyme binding
- heat shock protein binding
- high-density lipoprotein particle binding
- high-density lipoprotein particle receptor binding
- lipase inhibitor activity
- lipid binding
- lipid transporter activity
- phosphatidylcholine binding
- phosphatidylcholine-sterol O-acyltransferase activator activity
- phospholipid binding
- protein heterodimerization activity
- protein homodimerization activity
- receptor ligand activity
- signaling receptor binding
Cellular components
Protein domainsUniProt · Pfam · InterPro
- Apolipoprotein A-II (ApoA-II)
- Apolipoprotein A-II (ApoA-II) superfamily
- Apolipoprotein A-II (ApoA-II)
KeywordsUniProt
InteractionsUniProt · HPA
Protein binding partners of APOA2 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 APOA2 as an antibody target. Whether an autoantibody or antibody against APOA2 could matter depends on whether native APOA2 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.
APOA2 is annotated as secreted, so native APOA2 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 APOA2 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.
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