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Updated: Jan 11, 2026

Cholesterol Efflux Assay
Published on: March 6, 2012
Cholesterol Transport from ER to Outer Mitochondria by ERLIN2 in Steroid Metabolism
Himangshu S Bose1,2, William E Burak1,2, Randy M Whittal3
1Laboratory of Biochemistry, Biomedical Sciences, Mercer University School of Medicine, Savannah, Georgia, USA.
Abstract:
Cholesterol trafficking from the endoplasmic reticulum (ER) through the mitochondria-associated ER membrane (MAM) and finally to mitochondria is essential for mammalian survival. ER lipid raft-associated protein 2 (ERLIN2) scaffolds raft-like microdomains in the trans-Golgi network, endosomes, and plasma membrane. We found that ERLIN2 assists in rolling cholesterol trafficking-associated lipid vesicles by facilitating the intermediate folding of cholesterol trafficker steroidogenic acute regulatory protein (StAR) from the ER to MAM prior to delivery to the outer mitochondrial membrane. Each ERLIN2-StAR interaction is short. The absence of ERLIN2 ablates mitochondrial cholesterol transport. Over time, StAR association with ERLIN2 increases from the ER to MAM, thereby enhancing mitochondrial cholesterol transport. Thus, ERLIN2 is central for regulating mitochondrial cholesterol trafficking required for mitochondrial steroid metabolism.
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