ER-derived caveolin-coated vesicles transport newly synthesized cholesterol to the plasma membrane

Cholesterol must be precisely partitioned within cells, with the plasma membrane (PM) holding the highest levels. In contrast, the endoplasmic reticulum (ER)—the site of cholesterol synthesis—contains very little cholesterol. How newly synthesized cholesterol moves from the ER to the PM remains poorly defined. Here, we identify a COPII-independent trafficking route in which nascent cholesterol is exported via specialized cholesterol transport vesicles (CTVs). A genome-wide screen reveals that DEGS1-derived ceramide is essential for CTV formation at the ER. Biochemical purification shows that caveolins serve as the vesicle coat, and loss of caveolins eliminates CTV production. Silencing PACSINs or dynamins leads to intracellular accumulation of CTVs, suggesting impaired vesicle scission. CTV delivery to the PM depends on actin filaments and the motors MYO1C and MYO1E. In vitro reconstitution with giant unilamellar vesicles demonstrates that ceramide promotes inward budding, whereas CAV1 drives outward budding. This work identifies a previously unrecognized class of ER-derived, caveolin-coated vesicles that transport cholesterol to the PM.