This gene encodes a component of high density lipoproteins (HDL). Mice lacking the encoded protein have low HDL-cholesterol levels, smaller HDL particles, increased clearance of triglyceride-rich lipoproteins and insulin hypersensitivity. Transgenic mice overexpressing the encoded protein have elevated levels of HDL-cholesterol and show increased susceptibility to atherosclerosis. Alternative splicing of this gene results in multiple variants. [provided by RefSeq, Mar 2015]