A1120 is a selective non-retinoid ligand for retinol-binding protein 4 (RBP4). RBP4 transports retinol from the liver to extrahepatic tissues and RBP4 lowering is reported to improve insulin sensitivity in mice. A1120 is a high affinity non-retinoid ligand for RBP4 which disrupts the interaction between RBP4 and its binding partner transthyretin (TTR). It binds to the same site as retinol and induces changes in the orientation (compared to the retinol bound form) of loops at the RBP4-TTR interaction interface.A1120 lowers RBP4 and retinol levels in a dose-dependent manner, to a similar extent as seen with fenretinide. However, unlike fenretinide (Sigma# H7779), A1120 does not have beneficial effects on insulin resistance.
