Cell-surface receptors for retinol-binding protein

Target tissues for retinol have receptors to which retinol and retinol-binding protein complex (retinol-RBP) binds specifically. Following this binding, either the whole retinol-RBP is internalized into the cells of some tissues or only the retinol enters the cells in other tissues, with liberation of apo-RBP. However, uptake of free retinol is the preferred mode of cellular entry in keratinocytes.