STARD3 (StAR-Related Lipid Transfer Domain Containing 3): STARD3 is a protein that plays a crucial role in cholesterol trafficking and homeostasis within cells. It enables the transfer of cholesterol between endosomes and the plasma membrane or endoplasmic reticulum. As a member of the START domain family, STARD3 is vital for sterol and lipid transport. Alterations in its function can impact cellular cholesterol distribution, influencing membrane composition, signalling pathways, and potentially contributing to atherosclerosis.