StAR-related lipid transfer protein 4 (STARD4)

StAR-related lipid transfer protein 4 (STARD4) is a soluble, cytosolic lipid transfer protein belonging to the START (Steroidogenic Acute Regulatory protein-related lipid Transfer) domain-containing family. STARD4 primarily facilitates the non-vesicular, intracellular transport of cholesterol and related sterols, including 7-α-hydroxycholesterol and 7-hydroperoxycholesterol, between organelles such as the endoplasmic reticulum (ER), mitochondria, and lipid droplets, thus contributing to cholesterol homeostasis and metabolism within the cell. It displays a conserved fold with a hydrophobic tunnel suitable for sterol binding. Its expression is strongly regulated by cholesterol levels via SREBP-2 and is most abundant in liver and kidney. Overexpression of STARD4 increases the accumulation of cholesteryl esters and promotes bile acid synthesis, suggesting its activity enhances cholesterol trafficking to sites of esterification and steroid biosynthesis. Despite its key role in cholesterol handling, loss of STARD4 in mice results only in mild metabolic changes, likely due to compensation by related START domain proteins. There are no current therapeutic interventions or clinical biomarkers directly involving STARD4, and it is not considered a direct drug target or therapeutic receptor.

Other names

StAR related lipid transfer domain containing 4START domain-containing protein 4StARD4START domain containing 4Sterol regulated proteinStAR-related lipid transfer (START) domain containing 4

Because STARD4 is not a direct therapeutic target, there are no drug mechanisms of action associated.