[7] High levels of STARD4 increases the synthesis of bile acids and cholesterol esters in liver hepatocytes.

[9][10] Increases in levels of either master gene regulator SREBP-1a or SREBP2, which both promote the production of proteins involved in cholesterol synthesis, increase StarD4 levels in mouse liver.

[12] Mice without functional STARD4 weigh less and females tend to have lower cholesterol profiles.

The most dramatic change observed to date is a reduction in NPC-1, a protein involved in bringing cholesterol into cells.

The protein is 205 amino acids long in the human (224 in the mouse) and almost entirely consists of a StAR-related transfer (START) domain.