| Structural highlights
Disease
[APOA1_HUMAN] Defects in APOA1 are a cause of high density lipoprotein deficiency type 2 (HDLD2) [MIM:604091]; also known as familial hypoalphalipoproteinemia (FHA). Inheritance is autosomal dominant.[1] [2] Defects in APOA1 are a cause of the low HDL levels observed in high density lipoprotein deficiency type 1 (HDLD1) [MIM:205400]; also known as analphalipoproteinemia or Tangier disease (TGD). HDLD1 is a recessive disorder characterized by the absence of plasma HDL, accumulation of cholesteryl esters, premature coronary artery disease, hepatosplenomegaly, recurrent peripheral neuropathy and progressive muscle wasting and weakness. In HDLD1 patients, ApoA-I fails to associate with HDL probably because of the faulty conversion of pro-ApoA-I molecules into mature chains, either due to a defect in the converting enzyme activity or a specific structural defect in Tangier ApoA-I.[3] [4] Note=A mutation in APOA1 is the cause of amyloid polyneuropathy-nephropathy Iowa type (AMYLIOWA); also known as amyloidosis van Allen type or familial amyloid polyneuropathy type III. AMYLIOWA is a hereditary generalized amyloidosis due to deposition of amyloid mainly constituted by apolipoprotein A1. The clinical picture is dominated by neuropathy in the early stages of the disease and nephropathy late in the course. Death is due in most cases to renal amyloidosis. Severe peptic ulcer disease can occurr in some and hearing loss is frequent. Cataracts is present in several, but vitreous opacities are not observed.[5] [6] [7] [8] Defects in APOA1 are a cause of amyloidosis type 8 (AMYL8) [MIM:105200]; also known as systemic non-neuropathic amyloidosis or Ostertag-type amyloidosis. AMYL8 is a hereditary generalized amyloidosis due to deposition of apolipoprotein A1, fibrinogen and lysozyme amyloids. Viscera are particularly affected. There is no involvement of the nervous system. Clinical features include renal amyloidosis resulting in nephrotic syndrome, arterial hypertension, hepatosplenomegaly, cholestasis, petechial skin rash.[9] [10] [11]
Function
[APOA1_HUMAN] Participates in the reverse transport of cholesterol from tissues to the liver for excretion by promoting cholesterol efflux from tissues and by acting as a cofactor for the lecithin cholesterol acyltransferase (LCAT). As part of the SPAP complex, activates spermatozoa motility.[12]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The structure of truncated human apolipoprotein A-I (apo A-I), the major protein component of high density lipoprotein, has been determined at 4-A resolution. The crystals comprise residues 44-243 (exon 4) of apo A-I, a fragment that binds to lipid similarly to intact apo A-I and that retains the lipid-bound conformation even in the absence of lipid. The molecule consists almost entirely of a pseudo-continuous, amphipathic alpha-helix that is punctuated by kinks at regularly spaced proline residues; it adopts a shape similar to a horseshoe of dimensions 125 x 80 x 40 A. Four molecules in the asymmetric unit associate via their hydrophobic faces to form an antiparallel four-helix bundle with an elliptical ring shape. Based on this structure, we propose a model for the structure of apo A-I bound to high density lipoprotein.
Crystal structure of truncated human apolipoprotein A-I suggests a lipid-bound conformation.,Borhani DW, Rogers DP, Engler JA, Brouillette CG Proc Natl Acad Sci U S A. 1997 Nov 11;94(23):12291-6. PMID:9356442[13]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Nakata K, Kobayashi K, Yanagi H, Shimakura Y, Tsuchiya S, Arinami T, Hamaguchi H. Autosomal dominant hypoalphalipoproteinemia due to a completely defective apolipoprotein A-I gene. Biochem Biophys Res Commun. 1993 Oct 29;196(2):950-5. PMID:8240372 doi:http://dx.doi.org/S0006-291X(83)72341-7
- ↑ Ng DS, Leiter LA, Vezina C, Connelly PW, Hegele RA. Apolipoprotein A-I Q[-2]X causing isolated apolipoprotein A-I deficiency in a family with analphalipoproteinemia. J Clin Invest. 1994 Jan;93(1):223-9. PMID:8282791 doi:http://dx.doi.org/10.1172/JCI116949
- ↑ Nakata K, Kobayashi K, Yanagi H, Shimakura Y, Tsuchiya S, Arinami T, Hamaguchi H. Autosomal dominant hypoalphalipoproteinemia due to a completely defective apolipoprotein A-I gene. Biochem Biophys Res Commun. 1993 Oct 29;196(2):950-5. PMID:8240372 doi:http://dx.doi.org/S0006-291X(83)72341-7
- ↑ Ng DS, Leiter LA, Vezina C, Connelly PW, Hegele RA. Apolipoprotein A-I Q[-2]X causing isolated apolipoprotein A-I deficiency in a family with analphalipoproteinemia. J Clin Invest. 1994 Jan;93(1):223-9. PMID:8282791 doi:http://dx.doi.org/10.1172/JCI116949
- ↑ Nakata K, Kobayashi K, Yanagi H, Shimakura Y, Tsuchiya S, Arinami T, Hamaguchi H. Autosomal dominant hypoalphalipoproteinemia due to a completely defective apolipoprotein A-I gene. Biochem Biophys Res Commun. 1993 Oct 29;196(2):950-5. PMID:8240372 doi:http://dx.doi.org/S0006-291X(83)72341-7
- ↑ Ng DS, Leiter LA, Vezina C, Connelly PW, Hegele RA. Apolipoprotein A-I Q[-2]X causing isolated apolipoprotein A-I deficiency in a family with analphalipoproteinemia. J Clin Invest. 1994 Jan;93(1):223-9. PMID:8282791 doi:http://dx.doi.org/10.1172/JCI116949
- ↑ Nichols WC, Dwulet FE, Liepnieks J, Benson MD. Variant apolipoprotein AI as a major constituent of a human hereditary amyloid. Biochem Biophys Res Commun. 1988 Oct 31;156(2):762-8. PMID:3142462
- ↑ Nichols WC, Gregg RE, Brewer HB Jr, Benson MD. A mutation in apolipoprotein A-I in the Iowa type of familial amyloidotic polyneuropathy. Genomics. 1990 Oct;8(2):318-23. PMID:2123470
- ↑ Nakata K, Kobayashi K, Yanagi H, Shimakura Y, Tsuchiya S, Arinami T, Hamaguchi H. Autosomal dominant hypoalphalipoproteinemia due to a completely defective apolipoprotein A-I gene. Biochem Biophys Res Commun. 1993 Oct 29;196(2):950-5. PMID:8240372 doi:http://dx.doi.org/S0006-291X(83)72341-7
- ↑ Ng DS, Leiter LA, Vezina C, Connelly PW, Hegele RA. Apolipoprotein A-I Q[-2]X causing isolated apolipoprotein A-I deficiency in a family with analphalipoproteinemia. J Clin Invest. 1994 Jan;93(1):223-9. PMID:8282791 doi:http://dx.doi.org/10.1172/JCI116949
- ↑ Soutar AK, Hawkins PN, Vigushin DM, Tennent GA, Booth SE, Hutton T, Nguyen O, Totty NF, Feest TG, Hsuan JJ, et al.. Apolipoprotein AI mutation Arg-60 causes autosomal dominant amyloidosis. Proc Natl Acad Sci U S A. 1992 Aug 15;89(16):7389-93. PMID:1502149
- ↑ Akerlof E, Jornvall H, Slotte H, Pousette A. Identification of apolipoprotein A1 and immunoglobulin as components of a serum complex that mediates activation of human sperm motility. Biochemistry. 1991 Sep 17;30(37):8986-90. PMID:1909888
- ↑ Borhani DW, Rogers DP, Engler JA, Brouillette CG. Crystal structure of truncated human apolipoprotein A-I suggests a lipid-bound conformation. Proc Natl Acad Sci U S A. 1997 Nov 11;94(23):12291-6. PMID:9356442
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