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Updated: Jun 17, 2026

Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol
Published on: March 25, 2020
StarD4-mediated translocation of 7-hydroperoxycholesterol to isolated mitochondria: deleterious effects and
Witold Korytowski1, Daniel Rodriguez-Agudo, Anna Pilat
1Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Abstract:
StAR family proteins, including StarD4, play a key role in steroidogenesis by transporting cholesterol (Ch) into mitochondria for conversion to pregnenolone. Using a model system consisting of peroxidized cholesterol (7 alpha-OOH)-containing liposomes as donors, we showed that human recombinant StarD4 accelerates 7 alpha-OOH transfer to isolated liver mitochondria, and to a greater extent than Ch transfer. StarD4 had no effect on transfer of non-oxidized or peroxidized phosphatidylcholine, consistent with sterol ring specificity. StarD4-accelerated 7 alpha-OOH transfer to mitochondria resulted in greater susceptibility to free radical lipid peroxidation and loss of membrane potential than in a non-StarD4 control. The novel implication of these findings is that in oxidative stress states, inappropriate StAR-mediated trafficking of peroxidized Ch in steroidogenic tissues could result in damage and dysfunction selectively targeted to mitochondria.
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