STARD3 (StAR-Related Lipid Transfer Domain Containing 3): STARD3 is a protein that plays a key role in cholesterol trafficking and homeostasis within cells. It facilitates the movement of cholesterol between endosomes and the plasma membrane or endoplasmic reticulum. As a member of the START domain family, STARD3 is essential for sterol and lipid transport. Changes in its function can influence cellular cholesterol distribution, affecting membrane composition, signaling pathways, and potentially contributing to atherosclerosis.