Apolipoprotein A-IV (also known as apoA-IV, apoAIV, or apoA4) is plasma protein that is the product of the human
geneAPOA4.[5][6]
Gene
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]
Function
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:
^Luo CC, Li WH, Moore MN, Chan L (February 1986). "Structure and evolution of the apolipoprotein multigene family". J. Mol. Biol. 187 (3): 325–340.
doi:
10.1016/0022-2836(86)90436-5.
PMID3084795.
Kamboh MI, Williams ER, Law JC, et al. (1993). "Molecular basis of a unique African variant (A-IV 5) of human apolipoprotein A-IV and its significance in lipid metabolism". Genet. Epidemiol. 9 (6): 379–88.
doi:
10.1002/gepi.1370090602.
PMID1487136.
S2CID40107026.
Tenkanen H, Koskinen P, Metso J, et al. (1992). "A novel polymorphism of apolipoprotein A-IV is the result of an asparagine to serine substitution at residue 127". Biochim. Biophys. Acta. 1138 (1): 27–33.
doi:
10.1016/0925-4439(92)90147-f.
PMID1737067.
Wei S, Rocchi M, Archidiacono N, et al. (1990). "Physical mapping of the human chromosome 11q23 region containing the ataxia-telangiectasia locus". Cancer Genet. Cytogenet. 46 (1): 1–8.
doi:
10.1016/0165-4608(90)90002-R.
PMID2331673.
Yang CY, Gu ZW, Chong IS, et al. (1989). "The primary structure of human apolipoprotein A-IV". Biochim. Biophys. Acta. 1002 (2): 231–7.
doi:
10.1016/0005-2760(89)90292-0.
PMID2930771.
Karathanasis SK, Yunis I, Zannis VI (1986). "Structure, evolution, and tissue-specific synthesis of human apolipoprotein AIV". Biochemistry. 25 (13): 3962–70.
doi:
10.1021/bi00361a034.
PMID3755616.
Apolipoprotein A-IV (also known as apoA-IV, apoAIV, or apoA4) is plasma protein that is the product of the human
geneAPOA4.[5][6]
Gene
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]
Function
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:
^Luo CC, Li WH, Moore MN, Chan L (February 1986). "Structure and evolution of the apolipoprotein multigene family". J. Mol. Biol. 187 (3): 325–340.
doi:
10.1016/0022-2836(86)90436-5.
PMID3084795.
Kamboh MI, Williams ER, Law JC, et al. (1993). "Molecular basis of a unique African variant (A-IV 5) of human apolipoprotein A-IV and its significance in lipid metabolism". Genet. Epidemiol. 9 (6): 379–88.
doi:
10.1002/gepi.1370090602.
PMID1487136.
S2CID40107026.
Tenkanen H, Koskinen P, Metso J, et al. (1992). "A novel polymorphism of apolipoprotein A-IV is the result of an asparagine to serine substitution at residue 127". Biochim. Biophys. Acta. 1138 (1): 27–33.
doi:
10.1016/0925-4439(92)90147-f.
PMID1737067.
Wei S, Rocchi M, Archidiacono N, et al. (1990). "Physical mapping of the human chromosome 11q23 region containing the ataxia-telangiectasia locus". Cancer Genet. Cytogenet. 46 (1): 1–8.
doi:
10.1016/0165-4608(90)90002-R.
PMID2331673.
Yang CY, Gu ZW, Chong IS, et al. (1989). "The primary structure of human apolipoprotein A-IV". Biochim. Biophys. Acta. 1002 (2): 231–7.
doi:
10.1016/0005-2760(89)90292-0.
PMID2930771.
Karathanasis SK, Yunis I, Zannis VI (1986). "Structure, evolution, and tissue-specific synthesis of human apolipoprotein AIV". Biochemistry. 25 (13): 3962–70.
doi:
10.1021/bi00361a034.
PMID3755616.