Enables amyloid-beta binding activity; cholesterol transfer activity; and lipase inhibitor activity. Involved in several processes, including lipid transport; peripheral nervous system axon regeneration; and response to estrogen. Located in cell surface; extracellular space; and nucleus. Part of discoidal high-density lipoprotein particle; intermediate-density lipoprotein particle; and low-density lipoprotein particle. Used to study arteriosclerosis and hyperthyroidism. Biomarker of several diseases, including fatty liver disease (multiple); hypertension; major depressive disorder; ocular hypertension; and sciatic neuropathy. Human ortholog(s) of this gene implicated in several diseases, including artery disease (multiple); familial visceral amyloidosis; hypolipoproteinemia (multiple); non-alcoholic steatohepatitis; and systemic lupus erythematosus. Orthologous to human APOA1 (apolipoprotein A1). [provided by Alliance of Genome Resources, Apr 2022]