May stabilize HDL (high density lipoprotein) structure by its association with lipids, and affect the HDL metabolism. Monomer. Homodimer; disulfide-linked. Also forms a disulfide-linked heterodimer with APOD (PubMed:7918467). Interacts with NAXE and NDRG1. (Microbial infection) Interacts with HCV core protein. Plasma; synthesized in the liver and intestine. Phosphorylation sites are present in the extracellular medium. Apolipoprotein A-II is O-glycosylated. Homodimer, without methionine sulfoxide. Homodimer, with 1 methionine sulfoxide, oxidation at Met-49. Monomer. Cysteinylated ApoA-II monomer. Homodimer. Heterodimer with truncated apolipoprotein A-II. Monomer. Homodimer. Homodimer. A homozygous transition at position 1 of intron 3 of APOA2 results in deficiency of apolipoprotein A-II, without significant influence either on lipid and lipoprotein profiles or on the occurrence of coronary artery disease [MIM:107670]. Belongs to the apolipoprotein A2 family. A paper describing the crystal structure of this protein has been retracted due to evidence of fabricated data (see also US Office of Research Integrity Notice 2018-07782).