Apolipoprotein M (APOM)

Apolipoprotein M (ApoM) is a 26-kDa protein primarily associated with high-density lipoprotein (HDL) and, to a lesser extent, with low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) in human plasma[3][6][7]. It is encoded by the APOM gene and is a member of the lipocalin protein family[7]. ApoM contains an amphiphilic, lipocalin-type binding pocket that allows it to carry small lipophilic molecules, primarily sphingosine-1-phosphate (S1P), but also retinoids[5]. Functionally, ApoM serves as the principal carrier of S1P in plasma, delivering this bioactive lipid to its receptors on endothelial and other cells to help regulate vascular integrity, inflammation, and lipid metabolism[4][5]. ApoM is mainly expressed in the liver and kidney[3]. Reduced plasma levels or genetic alterations in APOM have been linked to increased risk for cardiovascular disease, atherosclerosis, diabetes (notably MODY3), inflammation, and possibly obesity[4][3]. ApoM plays both structural and regulatory roles in HDL metabolism and may contribute to anti-atherosclerotic effects via cholesterol efflux and anti-inflammatory activity[1][4]. While there are currently no approved drugs directly targeting ApoM itself, the ApoM/S1P axis is pharmacologically relevant owing to the clinical use of S1P receptor modulators in inflammatory and immune disorders[4].

Other names

ApoMG3ANG20HSPC336protein G3aapo-MNG20-like protein

Chaperoning and delivering S1P to S1P receptors on target cells, especially endothelial cells; modulating HDL function in lipid and cholesterol homeostasis[1][5].