This gene encodes an apolipoprotein which is the major protein component of very-low-density lipoproteins (VLDL) and a minor component of high-density lipoproteins (HDL). The encoded protein is thought to regulate the metabolism of triglyceride-rich lipoproteins and play a role in lipid storage and the mobilization of fat cells. This gene is clustered with three other apolipoprotein genes on chromosome 9 and is associated with coronary disease. Mice lacking this gene have lower levels of total cholesterol in the plasma. Mutations in the human genes causes hyperalphalipoproteinemia 2, a disorder of lipid metabolism which results in a favorable lipid profile (lower LDL-cholesterol, higher HDL-cholesterol and lower levels of serum triglycerides when fasting and after a meal). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2014]