Which statement regarding STRA6-mediated retinol uptake is best supported by the passage?
- Retinol uptake activity by STRA6 is limited without the presence of intracellular binding proteins.
- The expression of STRA6 is likely to be higher in the liver than in target organs.
- Retinol uptake activity by STRA6 is accelerated when retinol is stored as intracellular retinol rather than as retinyl esters.
- Binding of holo-RBP to STRA6 is likely to have a Hill coefficient greater than 1.