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5  structures 60  species 1  interaction 91  sequences 2  architectures

Family: ApoM (PF11032)

Summary: ApoM domain

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This is the Wikipedia entry entitled "APOM". More...

APOM Edit Wikipedia article

Apolipoprotein M
Protein APOM PDB 2WEW.png
Rendering based on PDB 2WEW.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols APOM ; G3a; HSPC336; NG20; apo-M
External IDs OMIM606907 MGI1930124 HomoloGene10308 GeneCards: APOM Gene
RNA expression pattern
PBB GE APOM 214910 s at tn.png
PBB GE APOM 205682 x at tn.png
More reference expression data
Species Human Mouse
Entrez 55937 55938
Ensembl ENSG00000204444 ENSMUSG00000024391
UniProt O95445 Q9Z1R3
RefSeq (mRNA) NM_001256169 NM_018816
RefSeq (protein) NP_001243098 NP_061286
Location (UCSC) Chr 6:
31.65 – 31.66 Mb
Chr 17:
35.13 – 35.13 Mb
PubMed search [1] [2]
Symbol ApoM
Pfam PF11032
Pfam clan CL0116
InterPro IPR022734

Apolipoprotein M is a protein that in humans is encoded by the APOM gene.[1][2][3]

The protein encoded by this gene is an apolipoprotein and member of the lipocalin protein family. It is found associated with high density lipoproteins and to a lesser extent with low density lipoproteins and triglyceride-rich lipoproteins. The encoded protein is secreted through the plasma membrane but remains membrane-bound, where it is involved in lipid transport. Two transcript variants encoding two different isoforms have been found for this gene, but only one of them has been fully characterized.[3]


  1. ^ Xu N, Dahlback B (Dec 1999). "A novel human apolipoprotein (apoM)". J Biol Chem 274 (44): 31286–90. doi:10.1074/jbc.274.44.31286. PMID 10531326. 
  2. ^ Duan J, Dahlback B, Villoutreix BO (Jun 2001). "Proposed lipocalin fold for apolipoprotein M based on bioinformatics and site-directed mutagenesis". FEBS Lett 499 (1–2): 127–32. doi:10.1016/S0014-5793(01)02544-3. PMID 11418126. 
  3. ^ a b "Entrez Gene: APOM apolipoprotein M". 

Further reading

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

ApoM domain Provide feedback

ApoM is a 25 kDa plasma protein associated with high-density lipoproteins (HDLs). ApoM is important in the formation of pre-ss-HDL and also in increasing cholesterol efflux from macrophage foam cells [1]. Lipoproteins consist of lipids solubilized by apolipoproteins. ApoM lacks an external amphipathic motif and is uniquely secreted to plasma without cleavage of its terminal signal peptide [2].

Literature references

  1. Ahnstrom J, Axler O, Jauhiainen M, Salomaa V, Havulinna AS, Ehnholm C, Frikke-Schmidt R, Tybjaerg-Hansen A, Dahlback B; , J Lipid Res. 2008; [Epub ahead of print]: Levels of apolipoprotein M are not associated with the risk of coronary heart disease in two independent case-control studies. PUBMED:18490703 EPMC:18490703

  2. Christoffersen C, Ahnstrom J, Axler O, Christensen EI, Dahlback B, Nielsen LB; , J Biol Chem. 2008; [Epub ahead of print]: The signal peptide anchors apolipoprotein M in plasma lipoproteins and prevents rapid clearance of apolipoprotein M from plasma. PUBMED:18460466 EPMC:18460466

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR022734

ApoM is a 25 kDa plasma protein associated with high-density lipoproteins (HDLs). ApoM is important in the formation of pre-ss-HDL and also in increasing cholesterol efflux from macrophage foam cells [PUBMED:18490703]. Lipoproteins consist of lipids solubilized by apolipoproteins. ApoM lacks an external amphipathic motif and is uniquely secreted to plasma without cleavage of its terminal signal peptide [PUBMED:18460466].

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan Calycin (CL0116), which has the following description:

The calycin structural superfamily [1-3] includes the lipocalins, the fatty acid-binding proteins (FABPs).

The clan contains the following 20 members:

ApoM CrtC DUF3642 DUF4488 DUF4822 His_binding Lipocalin Lipocalin_2 Lipocalin_3 Lipocalin_4 Lipocalin_5 Lipocalin_7 Lipocalin_8 META Nitrophorin NlpE Svf1 Triabin VDE ZinT


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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

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MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

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Curation and family details

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Seed source: PRODOM
Previous IDs: none
Type: Domain
Author: Pollington J, Finn RD
Number in seed: 2
Number in full: 91
Average length of the domain: 159.10 aa
Average identity of full alignment: 39 %
Average coverage of the sequence by the domain: 91.66 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 20.6 20.6
Trusted cut-off 20.7 20.7
Noise cut-off 20.5 20.1
Model length: 188
Family (HMM) version: 4
Download: download the raw HMM for this family

Species distribution

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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the ApoM domain has been found. There are 5 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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