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FLASH GENE
Symbol APOM contributors: mct - updated : 24-01-2020
HGNC name apolipoprotein M
HGNC id 13916
DNA
TYPE functioning gene
STRUCTURE 5.81 kb     6 Exon(s)    1 Copie(s)
10 Kb 5' upstream gene genomic sequence study
MAPPING cloned Y linked N status provisional
regionally located located between BAT3 and BAT4, located in the major histocompatibility complex class III region
RNA
TRANSCRIPTS type messenger
text two transcript variants encoding two different isoforms
identificationnb exonstypebpproduct
ProteinkDaAAspecific expressionYearPubmed
6 - 722 - 116 - 2003 12666989
6 - 761 - 188 - 2003 12666989
EXPRESSION
Type widely
   expressed in (based on citations)
organ(s)
SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
blood / hematopoieticspleen   highly
Cardiovascularheart    
Digestiveliver   predominantly Homo sapiens
Endocrineparathyroid   highly
Nervousbrain    
Respiratorylung    
Urinarykidney   predominantly Homo sapiens
tissue
SystemTissueTissue level 1Tissue level 2LevelPubmedSpeciesStageRna symbol
Blood / Hematopoietic    
Lymphoid    
cell lineage
cell lines
fluid/secretion plasma
at STAGE
PROTEIN
PHYSICAL PROPERTIES Hydrophobic
STRUCTURE
motifs/domains
  • a N terminal glycosylation site
  • two possible disulfide bridges
  • a hydrophobic alpha-helical signal peptide, that is necessary for its ability to associate with lipid
  • secondary structure an alpha helix, an eight-stranded anti-parallel beta barrel
    conjugated GlycoP , LipoP
    HOMOLOGY
    interspecies homolog to murine Apom
    homolog to Drosophila l(1)10Bb
    homolog to C.elegans C07A9.2
    Homologene
    FAMILY lipocalin protein family
    CATEGORY chaperone/stress , transport carrier
    SUBCELLULAR LOCALIZATION extracellular
        plasma membrane
    text secreted through the plasma membrane but remains membrane-bound
    basic FUNCTION
  • involved in the metabolism of lipids and lipoprotein particles
  • APOM, by delivering S1P to the S1P(1) receptor on endothelial cells, is a vasculoprotective constituent of HDL
  • APOM can bind oxidized phospholipids and increases the antioxidant effect of HDL
  • plasma APOM levels modulate the ability of plasma to mobilize cellular cholesterol, whereas APOM has no major effect on the excretion of cholesterol into feces
  • both APOM and APOA1 mRNA may considered as independent risk factors for macrosomia
  • APOM and S1P are key elements of the anti-apoptotic activity of HDL and promote optimal endothelial function
  • mediates sphingosine-1-phosphate efflux from erythrocytes
  • APOM plays a key role in normal autophagy activity in the liver and thereby further regulates the metabolism of liver lipids, particularly triglycerides
  • is the carrier of sphingosine-1-phosphate (S1P) in plasma high-density lipoproteins
  • is a chaperone for the bioactive sphingolipid, sphingosine-1-phosphate (S1P), which has a specific role in inflammation
  • is a carrier of sphingosine 1-phosphate (S1P), a multifunctional lipid mediator, on HDL, and the pleiotropic effects of HDL are believed to be mediated by S1P
  • APOM/S1P exerts likely protective roles against the development of insulin resistance
  • CELLULAR PROCESS
    PHYSIOLOGICAL PROCESS
    text lipid transport
    PATHWAY
    metabolism energetic , lipid/lipoprotein
    signaling
    membrane lipid metabolism, energy storage
    a component
  • minor component of high density lipoproteins (HDL),low density lipoproteins (LDL) as well as triglyceride-rich lipoproteins (TGRLP)
  • INTERACTION
    DNA
    RNA
    small molecule
    protein
  • associated with HDL
  • HDL facilitates S1P efflux from erythrocytes by both APOM-dependent and APOM-independent mechanisms
  • APOM suppressed TNF-induced expression of ICAM1 and VCAM1 through inhibiting the activity of NFKB1
  • APOM induces inhibition of inflammatory responses via the S1PR1 and DHCR24 pathways
  • is a minor HDL apolipoprotein and carrier for sphingosine-1-phosphate (S1P)
  • cell & other
    REGULATION
    induced by platelet-activating factor (PAF)
    ASSOCIATED DISORDERS
    corresponding disease(s)
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    constitutional     --low  
    in patients with type 2 diabetes mellitus
    constitutional     --low  
    plasma APOM levels were reduced in patients with chronic kidney disease (CKD) stages 3-5D as compared to patients with CKD stages 1 + 2 and controls
    tumoral     --over  
    mRNA levels in the colorectal cancer tissues were significantly increased in the patients with lymph node metastasis
    tumoral     --low  
    in hepatocellular carcinoma tissues
    Susceptibility
  • to venous thromboembolism (VTE)
  • Variant & Polymorphism
  • APOM rs805297 was significantly associated with higher risk of VTE recurrence in male but not in female patients
  • Candidate gene
    Marker
  • potential for APOM/S1P as biomarkers for inflammation, sepsis and nephropathy
  • Therapy target
    ANIMAL & CELL MODELS
  • lack of Apom in mice increases the amount of brown adipose tissue (BAT), accelerates the clearance of postprandial triglycerides, and protects against diet-induced obesity