Retinol Binding Protein-4 Signaling Pathway

1. Retinol Binding Protein-4 Signaling Pathway Retinol-binding protein 4 (RBP4), the sole retinol transporter in blood, is secreted from adipocytes and liver. Retinol (vitamin A) plays an important role in promoting the steady state of the animal's body. Its lack can lead to diseases such as night blindness and can lead to the reduction of energy resources and cell membrane destruction of embryos or eggs and affect the quality of embryos and eggs. Retinol-binding protein 4 (RBP4) is a member of the retinol-binding protein (RBP) family. The storage, absorption, and transport of retinol in the body must depend on the presence of RBP4, which is the only one that has been confirmed so far. A transporter that transports retinol in the blood, the main expression site is the liver, and other organs such as the kidney are also expressed. RBP4 can transport retinol and its active metabolites from the liver to the target tissue, assisting retinol to exert its physiological effects. RBP4 acts as a cellular messenger from fat cells. If it is lacking in the body, it will cause confusion in the distribution of retinol in tissues, which will affect the growth, differentiation, reproduction and embryonic development of bone and epithelial tissues, and further lead to diseases such as night blindness. For humans, RBP4 levels are reduced with retinol (VitA) deficiency, hypoproteinemia, malabsorption syndrome, liver disease (except over-nutrition fatty liver), hyperthyroidism, etc.; RBP4 decline in serum can also cause acute and chronic hepatitis and cirrhosis. If the RBP4 content in the body is higher than the threshold, it will cause renal insufficiency and overnutrition. Studies have reported that serum RBP4 levels are associated with multiple metabolic parameters such as waist circumference, BMI, and TG. More studies now suggest that RBP4, as a cytokine, can participate in the process of obesity, type 2 diabetes, and insulin resistance by regulating lipid metabolism. At the same time, RBP4 plays a role in the pathogenesis of sex hormone-related diseases. Serum RBP4 levels are positively correlated with testosterone and negatively correlated with sex hormone binding protein (SHBG) and are higher in men than in women. Find more at: https://www.creative-diagnostics.com/retinol-binding-protein-4-signaling-pathway.h tm