Noy Noa, Li Li, Abola Matthew V, Berger Nathan A
Horm Mol Biol Clin Investig. 2015 Aug;23(2):39-46. doi: 10.1515/hmbci-2015-0019.
Retinol binding protein 4 (RBP4) is synthesized in the liver where it binds vitamin A, retinol, and transports it to tissues throughout the body. It has been shown in some studies that the level of circulating RBP4 increases with body mass, and the protein has been implicated as a mediator in the development of insulin resistance and the metabolic disease. Adipose tissue serves as another site of RBP4 synthesis, accounting for its designation as an adipokine. In addition to its function as a transport protein, RBP4 serves as a signaling molecule which, by binding to the membrane receptor STRA6, triggers downstream activation of pro-oncogenic pathways including JAK2/STAT3/5. Taken together, available information suggests the possibility that RBP4 may be a link between obesity and cancer.
视黄醇结合蛋白4（RBP4）在肝脏中合成，在肝脏中它与维生素A、视黄醇结合，并将其输送到全身组织。一些研究表明，循环中的RBP4水平随体重增加而升高，并且该蛋白被认为是胰岛素抵抗和代谢性疾病发展的介质。脂肪组织是RBP4合成的另一个部位，这使其被归类为脂肪因子。除了作为转运蛋白的功能外，RBP4还作为信号分子，通过与膜受体STRA6结合，触发包括JAK2/STAT3/5在内的促癌通路的下游激活。综合来看，现有信息表明RBP4可能是肥胖与癌症之间的一个联系。
