Lipoprotein and membrane transporters for beta-carotene

General carrier proteins for beta-carotene refers to the collective group of proteins and lipoprotein complexes that facilitate the absorption, transport, and cellular uptake of beta-carotene, a primary provitamin A carotenoid. Because beta-carotene is highly lipophilic, it cannot circulate freely in the aqueous environment of the blood and is instead packaged into lipoproteins, primarily Low-Density Lipoprotein (LDL) and High-Density Lipoprotein (HDL) (Erdman et al., 1993; Harrison, 2012). In the small intestine, the uptake of beta-carotene from dietary micelles into enterocytes is mediated by membrane transporters such as Scavenger Receptor Class B Member 1 (SR-B1) and Cluster of Differentiation 36 (CD36) (Reboul, 2013; Borel et al., 2013). Once inside the cell, beta-carotene can be cleaved by the enzyme beta-carotene 15,15'-monooxygenase (BCO1) to form retinal or be secreted into the lymphatic system within chylomicrons (von Lintig, 2010). While these carriers are not typically the primary targets of drug therapy, medications that alter lipid metabolism—such as statins, ezetimibe, and orlistat—can significantly impact the bioavailability and systemic levels of beta-carotene (Frei et al., 1988; During et al., 2002). Understanding these transport mechanisms is crucial for addressing vitamin A deficiency and optimizing the delivery of antioxidant carotenoids in clinical settings.

Other names

General carrier proteins for beta-caroteneCarotenoid transport proteinsBeta-carotene carriersScavenger receptor class B member 1 (SR-B1)Cluster of differentiation 36 (CD36)Low-density lipoprotein (LDL)High-density lipoprotein (HDL)

Inhibition of intestinal absorption via NPC1L1/SR-B1 or reduction of circulating lipoprotein carriers