APOM

Apolipoprotein M is an apolipoprotein and member of the lipocalin protein family that in humans is encoded by the APOM gene. 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. It lacks an external amphipathic motif and is uniquely secreted to plasma without cleavage of its terminal signal peptide. The average molecular weight is 21253 Da, and the monoisotopic molecular weight is 21239 Da.

APOM
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2WEW, 2WEX, 2YG2
Identifiers
Aliases	APOM, G3a, HSPC336, NG20, apo-M, apolipoprotein M
External IDs	OMIM: 606907; MGI: 1930124; HomoloGene: 10308; GeneCards: APOM; OMA:APOM - orthologs
Gene location (Human) Chr. Chromosome 6 (human) Band 6p21.33 Start 31,652,416 bp End 31,658,210 bp
Gene location (Mouse) Chr. Chromosome 17 (mouse) Band 17|17 B1 Start 35,347,973 bp End 35,351,026 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in right lobe of liver human kidney gonad renal cortex testicle left testis right testis olfactory zone of nasal mucosa gastrocnemius muscle bone marrow Top expressed in yolk sac left lobe of liver right kidney human fetus human kidney proximal tubule primitive streak fetal liver hematopoietic progenitor cell abdominal wall blastocyst More reference expression data BioGPS More reference expression data
Gene ontology Molecular function lipid transporter activity antioxidant activity phospholipid binding Cellular component discoidal high-density lipoprotein particle integral component of plasma membrane very-low-density lipoprotein particle spherical high-density lipoprotein particle extracellular region low-density lipoprotein particle high-density lipoprotein particle extracellular space Biological process lipoprotein metabolic process lipid transport negative regulation of plasma lipoprotein oxidation response to glucose high-density lipoprotein particle assembly retinoid metabolic process high-density lipoprotein particle remodeling cholesterol efflux cholesterol homeostasis reverse cholesterol transport high-density lipoprotein particle clearance cellular oxidant detoxification Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 55937 55938 Ensembl ENSG00000231974 ENSG00000204444 ENSG00000206409 ENSG00000227567 ENSG00000235754 ENSG00000224290 ENSG00000226215 ENSMUSG00000024391 UniProt O95445 Q9Z1R3 RefSeq (mRNA) NM_001256169 NM_019101 NM_018816 RefSeq (protein) NP_001243098 NP_061974 NP_061286 Location (UCSC) Chr 6: 31.65 – 31.66 Mb Chr 17: 35.35 – 35.35 Mb PubMed search
Wikidata
View/Edit Human View/Edit Mouse

ApoM
Identifiers
Symbol	ApoM
Pfam	PF11032
Pfam clan	CL0116
InterPro	IPR022734
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Further reading

• Albertella MR, Jones H, Thomson W, Olavesen MG, Campbell RD (September 1996). "Localization of eight additional genes in the human major histocompatibility complex, including the gene encoding the casein kinase II beta subunit (CSNK2B)". Genomics. 36 (2): 240–251. doi:10.1006/geno.1996.0459. PMID 8812450.
• Xu N, Zhang XY, Dong X, Ekström U, Ye Q, Nilsson-Ehle P (April 2002). "Effects of platelet-activating factor, tumor necrosis factor, and interleukin-1alpha on the expression of apolipoprotein M in HepG2 cells". Biochemical and Biophysical Research Communications. 292 (4): 944–950. doi:10.1006/bbrc.2002.6755. PMID 11944906.
• Strausberg RL, Feingold EA, Grouse LH, Derge JG, Klausner RD, Collins FS, et al. (December 2002). "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences". Proceedings of the National Academy of Sciences of the United States of America. 99 (26): 16899–16903. Bibcode:2002PNAS...9916899M. doi:10.1073/pnas.242603899. PMC 139241. PMID 12477932.
• Zhang XY, Dong X, Zheng L, Luo GH, Liu YH, Ekström U, et al. (2003). "Specific tissue expression and cellular localization of human apolipoprotein M as determined by in situ hybridization". Acta Histochemica. 105 (1): 67–72. doi:10.1078/0065-1281-00687. PMID 12666989.
• Richter S, Shih DQ, Pearson ER, Wolfrum C, Fajans SS, Hattersley AT, Stoffel M (December 2003). "Regulation of apolipoprotein M gene expression by MODY3 gene hepatocyte nuclear factor-1alpha: haploinsufficiency is associated with reduced serum apolipoprotein M levels". Diabetes. 52 (12): 2989–2995. doi:10.2337/diabetes.52.12.2989. PMID 14633861.
• Xie T, Rowen L, Aguado B, Ahearn ME, Madan A, Qin S, et al. (December 2003). "Analysis of the gene-dense major histocompatibility complex class III region and its comparison to mouse". Genome Research. 13 (12): 2621–2636. doi:10.1101/gr.1736803. PMC 403804. PMID 14656967.
• Zhang XY, Jiao GQ, Hurtig M, Dong X, Zheng L, Luo GH, et al. (2005). "Expression pattern of apolipoprotein M during mouse and human embryogenesis". Acta Histochemica. 106 (2): 123–128. doi:10.1016/j.acthis.2003.11.004. PMID 15147633.
• Kabbara A, Payet N, Cottel D, Frigard B, Amouyel P, Lambert JC (June 2004). "Exclusion of CYP46 and APOM as candidate genes for Alzheimer's disease in a French population". Neuroscience Letters. 363 (2): 139–143. doi:10.1016/j.neulet.2004.03.066. PMID 15172102. S2CID 27752858.
• Xu N, Nilsson-Ehle P, Ahrén B (October 2004). "Correlation of apolipoprotein M with leptin and cholesterol in normal and obese subjects". The Journal of Nutritional Biochemistry. 15 (10): 579–582. doi:10.1016/j.jnutbio.2004.03.001. PMID 15542348.
• Luo G, Hurtig M, Zhang X, Nilsson-Ehle P, Xu N (May 2005). "Leptin inhibits apolipoprotein M transcription and secretion in human hepatoma cell line, HepG2 cells". Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids. 1734 (2): 198–202. doi:10.1016/j.bbalip.2005.02.005. PMID 15904876.
• Liu T, Qian WJ, Gritsenko MA, Camp DG, Monroe ME, Moore RJ, Smith RD (2006). "Human plasma N-glycoproteome analysis by immunoaffinity subtraction, hydrazide chemistry, and mass spectrometry". Journal of Proteome Research. 4 (6): 2070–2080. doi:10.1021/pr0502065. PMC 1850943. PMID 16335952.
• Niu N, Zhu X, Liu Y, Du T, Wang X, Chen D, et al. (January 2007). "Single nucleotide polymorphisms in the proximal promoter region of apolipoprotein M gene (apoM) confer the susceptibility to development of type 2 diabetes in Han Chinese". Diabetes/Metabolism Research and Reviews. 23 (1): 21–25. doi:10.1002/dmrr.641. PMID 16572495. S2CID 21156244.
• Christoffersen C, Nielsen LB, Axler O, Andersson A, Johnsen AH, Dahlbäck B (August 2006). "Isolation and characterization of human apolipoprotein M-containing lipoproteins". Journal of Lipid Research. 47 (8): 1833–1843. doi:10.1194/jlr.M600055-JLR200. PMID 16682745.
• Karlsson H, Lindqvist H, Tagesson C, Lindahl M (October 2006). "Characterization of apolipoprotein M isoforms in low-density lipoprotein". Journal of Proteome Research. 5 (10): 2685–2690. doi:10.1021/pr060180x. PMID 17022639.
• Xu X, Ye Q, Xu N, He X, Luo G, Zhang X, et al. (November 2006). "Effects of ischemia-reperfusion injury on apolipoprotein M expression in the liver". Transplantation Proceedings. 38 (9): 2769–2773. doi:10.1016/j.transproceed.2006.08.133. PMID 17112825.
• Ahnström J, Faber K, Axler O, Dahlbäck B (August 2007). "Hydrophobic ligand binding properties of the human lipocalin apolipoprotein M". Journal of Lipid Research. 48 (8): 1754–1762. doi:10.1194/jlr.M700103-JLR200. PMID 17525477.

External links

• Applied Research on apoM
• Human APOM genome location and APOM gene details page in the UCSC Genome Browser.
• Overview of all the structural information available in the PDB for UniProt: O95445 (Human Apolipoprotein M) at the PDBe-KB.