8.A.180. The Retinol-binding protein (RBP) Family
RBP4 mediates retinol transport in blood plasma (Peterson 1971). It delivers retinol from the liver stores to the peripheral tissues and transfers the bound all-trans retinol to STRA6, that then facilitates retinol transport across the cell membrane (Berry et al. 2012). It is a small molecule transporter (Xiong et al. 2021).
Retinal binding protein-4, RBP4 of 201 aas and one possible N-terminal TMS. See family description for details (Xiong et al. 2021).
RBP4 of Homo sapiens
Apolipoprotein D of 184 aas and possibly 2 TMSs, one at the N-terminus and one near the C-terminus.
Apolipoprotein D of Nephila pilipes (giant wood spider)
Lipocalin family protein of 153 aas with one N-terminal TMS.
Lipocalin-like protein of Chryseobacterium sp. POL2