| APOA4 | |||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Aliases | APOA4 , apolipoprotein A4 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | OMIM: 107690 MGI: 88051 HomoloGene: 47927 GeneCards: APOA4 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
| Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||
Apolipoprotein A-IV (also known as apoA-IV, apoAIV, or apoA4) is plasma protein that is the product of the human gene APOA4. [5] [6]
APOA4 resides on chromosome 11 in close linkage to APOA1 and APOC3. APOA4 contains 3 exons separated by two introns, and is polymorphic, although most of the reported sequence polymorphisms occur in exon 3. The best validated and studied non-synonymous SNPs are a glutamine → histidine substitution at codon 360 and a threonine → serine substitution at codon 347; a sequence polymorphism has also been identified in the 3'UTR of the third exon. [7] Intra-species comparative gene sequence analysis suggests that the APOA4 gene arose from APOA1 by gene duplication approximately 270 MYA. [8]
The primary translation product of the APOA4 gene is a 396-residue preprotein, which undergoes proteolytic processing to yield apo A-IV, a 376-residue mature O-linked glycoprotein. In most mammals, including humans, apo A-IV synthesis is confined to the intestine; however in mice and rats hepatic synthesis also occurs. Apo A-IV is secreted into circulation on the surface of newly synthesized chylomicron particles. Intestinal fat absorption dramatically increases the synthesis and secretion of apo A-IV. Although its primary function in human lipid metabolism has not been established, apo A-IV has been found to:
Human apo A-IV deficiency has not been reported.
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
Lipoprotein lipase (LPL) (EC 3.1.1.34, systematic name triacylglycerol acylhydrolase (lipoprotein-dependent)) is a member of the lipase gene family, which includes pancreatic lipase, hepatic lipase, and endothelial lipase. It is a water-soluble enzyme that hydrolyzes triglycerides in lipoproteins, such as those found in chylomicrons and very low-density lipoproteins (VLDL), into two free fatty acids and one monoacylglycerol molecule:
Apolipoproteins are proteins that bind lipids to form lipoproteins. They transport lipids in blood, cerebrospinal fluid and lymph.
Apolipoprotein B (ApoB) is a protein that in humans is encoded by the APOB gene.
Apolipoprotein C-II, or apolipoprotein C2 is a protein that in humans is encoded by the APOC2 gene.
Apolipoprotein C-I is a protein component of lipoproteins that in humans is encoded by the APOC1 gene.
Apolipoprotein AI(apoA-I) is a protein that in humans is encoded by the APOA1 gene. As the major component of HDL particles, it has a specific role in lipid metabolism.
Apolipoprotein C-III also known as apo-CIII, and apolipoprotein C3, is a protein that in humans is encoded by the APOC3 gene. Apo-CIII is secreted by the liver as well as the small intestine, and is found on triglyceride-rich lipoproteins such as chylomicrons, very low density lipoprotein (VLDL), and remnant cholesterol.
Apolipoprotein C-IV, also known as apolipoprotein C4, is a protein that in humans is encoded by the APOC4 gene.
Apolipoprotein D(ApoD) is a protein that in humans is encoded by the APOD gene. Unlike other lipoproteins, which are mainly produced in the liver, apolipoprotein D is mainly produced in the brain and testes. It is a 29 kDa glycoprotein discovered in 1963 as a component of the high-density lipoprotein (HDL) fraction of human plasma. It is the major component of human mammary cyst fluid. The human gene encoding it was cloned in 1986 and the deduced protein sequence revealed that ApoD is a member of the lipocalin family, small hydrophobic molecule transporters. ApoD is 169 amino acids long, including a secretion peptide signal of 20 amino acids. It contains two glycosylation sites and the molecular weight of the mature protein varies from 20 to 32 kDa.
Apolipoprotein A-V is a protein that in humans is encoded by the APOA5 gene on chromosome 11. It is significantly expressed in liver. The protein encoded by this gene is an apolipoprotein and an important determinant of plasma triglyceride levels, a major risk factor for coronary artery disease. It is a component of several lipoprotein fractions including VLDL, HDL, chylomicrons. It is believed that apoA-V affects lipoprotein metabolism by interacting with LDL-R gene family receptors. Considering its association with lipoprotein levels, APOA5 is implicated in metabolic syndrome. The APOA5 gene also contains one of 27 SNPs associated with increased risk of coronary artery disease.
Apolipoprotein A-II is a protein that in humans is encoded by the APOA2 gene.
Phospholipid transfer protein is a protein that in humans is encoded by the PLTP gene.
Fibrinogen beta chain, also known as FGB, is a gene found in humans and most other vertebrates with a similar system of blood coagulation.
Microsomal triglyceride transfer protein large subunit is a protein that in humans is encoded by the MTTP gene.
Plasma membrane calcium-transporting ATPase 2 is an enzyme that in humans is encoded by the ATP2B2 gene.
ATP-binding cassette sub-family G member 8 is a protein that in humans is encoded by the ABCG8 gene.
Apolipoprotein M is a protein that in humans is encoded by the APOM gene.
Collagen alpha-1(XIII) chain is a protein that in humans is encoded by the COL13A1 gene.
Plasma membrane calcium-transporting ATPase 3 is an enzyme that in humans is encoded by the ATP2B3 gene.
Apolipoprotein F is a protein that in humans is encoded for by the APOF gene.
 | This article on a gene on human chromosome 11 is a stub. You can help Wikipedia by expanding it. |
