Steroidogenic acute regulatory protein (StAR) plays a significant role in cholesterol transport from the cytoplasmic outer membrane to the inner mitochondrial membrane (1). The 37 kDa precursor is cleaved to generate an active 28 kDa protein capable of facilitating cholesterol metabolism into pregnenolone (2,3). StAR is prevalently expressed in mitochondria of steroid-producing adrenal and gonadal tissue (3). Abnormalities in StAR gene expression are impacted in autosomal Lipoid Congenial Adrenal Hyperplasia (LCAH) resulting in defects in pregnenolone and cortisol synthesis (4). The mechanism of cholesterol binding to StAR has yet to be elucidated (4).
