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FLASH GENE

Symbol

APOM

contributors: mct - updated : 24-01-2020

HGNC name	apolipoprotein M
HGNC id	13916

FLASH GENE DNA RNA EXPRESSION PROTEIN DISORDER ANIMAL & CELL MODELS

Location	6p21.33      Physical location : 2.909.249 - 31.625.986
Synonym name	NG20-like protein
Synonym symbol(s)	G3A, NG20, HSPC336, DADB-127H9.5, G3a, MGC22400

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

identification nb exons type bp product Protein kDa AA specific expression Year Pubmed NM_001256169 6 - 722 NP_001243098 - 116 - 2003 12666989 NM_019101 6 - 761 NP_061974 - 188 - 2003 12666989

EXPRESSION

Type

widely

expressed in	(based on citations)
organ(s)	System Organ level 1 Organ level 2 Organ level 3 Organ level 4 Level Pubmed Species Stage Rna symbol blood / hematopoietic spleen       highly Cardiovascular heart         Digestive liver       predominantly Homo sapiens Endocrine parathyroid       highly Nervous brain         Respiratory lung         Urinary kidney       predominantly Homo sapiens

tissue

System Tissue Tissue level 1 Tissue level 2 Level Pubmed Species Stage Rna 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)

Type Gene Modification Chromosome rearrangement Protein expression Protein 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