Predicted to enable several functions, including cation binding activity; cholesterol binding activity; and cholesterol transfer activity. Involved in peripheral nervous system axon regeneration and response to triglyceride. Part of chylomicron. Is active in synapse. Biomarker of major depressive disorder. Human ortholog(s) of this gene implicated in Alzheimer's disease; colitis; myocardial infarction; and ulcerative colitis. Orthologous to human APOA4 (apolipoprotein A4). [provided by Alliance of Genome Resources, Apr 2022]