FLVCR2

Choline uniporter that specifically mediates choline uptake at the blood-brain-barrier. Responsible for the majority of choline uptake across the blood-brain-barrier from the circulation into the brain (By similarity). Choline, a nutrient critical for brain development, is a precursor of phosphatidylcholine, as well as betaine (By similarity). Also mediates transport of ethanolamine. Choline and ethanolamine transport is not coupled with proton transport and is exclusively driven by the choline gradient across the plasma membrane. However, the presence of an inwardly directed proton gradient enhances choline uptake (By similarity). Also acts as a heme b transporter. Required to regulate mitochondrial respiration processes, ATP synthesis and thermogenesis. At low heme levels, interacts with components of electron transfer chain (ETC) complexes and ATP2A2, leading to ubiquitin-mediated degradation of ATP2A2 and inhibition of thermogenesis. Upon heme binding, dissociates from ETC complexes to allow switching from mitochondrial ATP synthesis to thermogenesis..

Function from UniProtKB (Q9UPI3), read 2026-09-23. CC BY 4.0.