InterPro : IPR002969

Name  Apolipoprotein D Short Name  ApolipopD
Type  Family Description  The outlier lipocalins form several smaller distinct subgroups: the OBPs, the von Ebner's gland proteins, alpha-1-acid glycoproteins, tick histamine binding proteins and the nitrophorins.Apolipoprotein D (apoD) is a mammalian plasma protein. Although well characterised, its precise biological function remains unclear. The majority of apoD constitutes a minor but significant protein component of high density lipoprotein particles (HDLs), representing about 5% of total HDL protein,and that its interaction with other apolipoproteins is of considerableimportance [, ]. By contrast with most apolipoproteins, human apoD is relatively small (189 residues, MW 18500). ApoD is 18% glycosylated, ateither or both of two asparagines (positions 65 and 98 []). Human apoD is distributed in a number of tissues, including kidney, liver, pancreas, spleen, intestine, placenta, adrenal gland and foetal brain tissue []. There is some evidence that the expression of apoD is regulated by steroidhormones []. ApoD is found in a number of mammalian species, including humans and other primates, rats, rabbits and goats, but it is absent from pigs, dogs, cows andhorses. The gene sequences of human, rat and rabbit apoD are of similar length and are well conserved.Analysis of the human sequence revealed that apoD is a lipocalin family member showing the greatest apparent similarity to insect colourant proteins.The expected 8-membered beta-barrel structure of ApoD contrasts with the structure of other apoliproteins. Apoliprotein A is a modular protein knownto be composed of several kringle domains, whilst apolipoprotein E and apophorin E are helix bundles. Membership of the lipocalin family suggests apoD may function by binding ahydrophobic ligand; the nature of this molecule remains uncertain, althoughcholesterol, bilin, progesterone and pregnenolone have all been suggested.Almost all apoD in plasma is found as part of a supramolecular complex. It is localised primarily in an HDL, with most of the remainder in very high density lipoprotein (VHDL) particles, and only trace amounts in low density lipoprotein (LDL) and very low density lipoprotein (VLDL) particles. TheapoD protein contains two distinct antigenic sites, which are apparently shared by other, higher molecular weight plasma proteins []. High concentrations of ApoD in some tisues are correlated with disease. A high concentration is found in cyst fluid of women with gross cystic disease of the breast, while it has also been shown to accumulate at sites of regenerating peripheral nerves, and in the cerebrospinal fluid of patients with neurodegenerative conditions, such as Alzheimer's disease. ApoD may, therefore, participate in maintenance and repair within the central and peripheral nervous systems. It is likely to be a multifunctional transporter capable of binding many different ligands: it has been shown to bind bind cholesterol, progesterone, pregnenolone, bilirubin and arachidonic acid, though it is not clear if these represent its physiological ligands. Possible roles for ApoD include the transport of ligands from one cell to another within an organ, scavenging of a ligand within an organ for transport to the blood, or transport of a ligand from the circulatory system to specific cells within a tissue. For more information see [].

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



1 Child Features

Id Name Short Name Type
IPR026222 Apolipoprotein D, vertebrates ApoD_vertbrte Family

4 Contains

Id Name Short Name Type
IPR000566 Lipocalin/cytosolic fatty-acid binding domain Lipocln_cytosolic_FA-bd_dom Domain
IPR011038 Calycin-like Calycin-like Domain
IPR012674 Calycin Calycin Domain
IPR022272 Lipocalin family conserved site Lipocalin_CS Conserved_site

0 Found In

1 Parent Features

Id Name Short Name Type
IPR022271 Lipocalin, ApoD type Lipocalin_ApoD Family

6 Publications

First Author Title Year Journal Volume Pages
Fielding PE A cholesteryl ester transfer complex in human plasma. 1980 Proc Natl Acad Sci U S A 77 3327-30
Albers JJ Characterization and immunoassay of apolipoprotein D. 1981 Atherosclerosis 39 395-409
Drayna D Cloning and expression of human apolipoprotein D cDNA. 1986 J Biol Chem 261 16535-9
Drayna DT Human apolipoprotein D gene: gene sequence, chromosome localization, and homology to the alpha 2u-globulin superfamily. 1987 DNA 6 199-204
Simard J Stimulation of apolipoprotein D secretion by steroids coincides with inhibition of cell proliferation in human LNCaP prostate cancer cells. 1991 Cancer Res 51 4336-41
Rassart E Apolipoprotein D. 2000 Biochim Biophys Acta 1482 185-98

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)