Q9GLC0 · APOE_TUPGL
- ProteinApolipoprotein E
- GeneAPOE
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids313 (go to sequence)
- Protein existenceEvidence at transcript level
- Annotation score5/5
Function
function
APOE is an apolipoprotein, a protein associating with lipid particles, that mainly functions in lipoprotein-mediated lipid transport between organs via the plasma and interstitial fluids. APOE is a core component of plasma lipoproteins and is involved in their production, conversion and clearance. Apolipoproteins are amphipathic molecules that interact both with lipids of the lipoprotein particle core and the aqueous environment of the plasma. As such, APOE associates with chylomicrons, chylomicron remnants, very low density lipoproteins (VLDL) and intermediate density lipoproteins (IDL) but shows a preferential binding to high-density lipoproteins (HDL). It also binds a wide range of cellular receptors including the LDL receptor/LDLR and the very low-density lipoprotein receptor/VLDLR that mediate the cellular uptake of the APOE-containing lipoprotein particles. Finally, APOE has also a heparin-binding activity and binds heparan-sulfate proteoglycans on the surface of cells, a property that supports the capture and the receptor-mediated uptake of APOE-containing lipoproteins by cells.
Features
Showing features for binding site.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Binding site | 158-161 | heparin (UniProtKB | ChEBI) | |||
Binding site | 225-232 | heparin (UniProtKB | ChEBI) | |||
GO annotations
Keywords
- Molecular function
- Biological process
- Ligand
Names & Taxonomy
Protein names
- Recommended nameApolipoprotein E
- Short namesApo-E
Gene names
Organism names
- Taxonomic lineageEukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Euarchontoglires > Scandentia > Tupaiidae > Tupaia
Accessions
- Primary accessionQ9GLC0
Subcellular Location
UniProt Annotation
GO Annotation
Note: In the plasma, APOE is associated with chylomicrons, chylomicrons remnants, VLDL, LDL and HDL lipoproteins. Lipid poor oligomeric APOE is associated with the extracellular matrix in a calcium- and heparan-sulfate proteoglycans-dependent manner. Lipidation induces the release from the extracellular matrix. Colocalizes with CD63 and PMEL at exosomes and in intraluminal vesicles within multivesicular endosomes.
Keywords
- Cellular component
PTM/Processing
Features
Showing features for signal, chain, modified residue.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Signal | 1-18 | ||||
Chain | PRO_0000001998 | 19-313 | Apolipoprotein E | ||
Modified residue | 139 | Methionine sulfoxide | |||
Modified residue | 143 | Phosphoserine | |||
Post-translational modification
APOE exists as multiple glycosylated and sialylated glycoforms within cells and in plasma. The extent of glycosylation and sialylation are tissue and context specific.
Glycated in plasma VLDL.
Phosphorylated by FAM20C in the extracellular medium.
Keywords
- PTM
Interaction
Subunit
Homotetramer. May interact with ABCA1; functionally associated with ABCA1 in the biogenesis of HDLs. May interact with APP/A4 amyloid-beta peptide; the interaction is extremely stable in vitro but its physiological significance is unclear. May interact with MAPT. May interact with MAP2. In the cerebrospinal fluid, interacts with secreted SORL1. Interacts with PMEL; this allows the loading of PMEL luminal fragment on ILVs to induce fibril nucleation.
Structure
Family & Domains
Features
Showing features for repeat, region.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Repeat | 76-97 | 1 | |||
Region | 76-251 | 8 X 22 AA approximate tandem repeats | |||
Repeat | 98-119 | 2 | |||
Repeat | 120-141 | 3 | |||
Repeat | 142-163 | 4 | |||
Region | 154-164 | LDL and other lipoprotein receptors binding | |||
Repeat | 164-185 | 5 | |||
Repeat | 186-207 | 6 | |||
Region | 206-286 | Lipid-binding and lipoprotein association | |||
Repeat | 208-229 | 7 | |||
Repeat | 230-251 | 8 | |||
Region | 262-313 | Homooligomerization | |||
Region | 274-286 | Specificity for association with VLDL | |||
Sequence similarities
Belongs to the apolipoprotein A1/A4/E family.
Keywords
- Domain
Family and domain databases
Sequence
- Sequence statusComplete
- Sequence processingThe displayed sequence is further processed into a mature form.
- Length313
- Mass (Da)35,923
- Last updated2001-03-01 v1
- Checksum015D4D91F1D905BA
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
AF303830 EMBL· GenBank· DDBJ | AAG21401.1 EMBL· GenBank· DDBJ | mRNA |