RBP2 (retinol binding protein 2) is a 16 kDa cytosolic protein primarily localized to absorptive cells of the proximal small intestine that serves dual functions in retinoid and lipid metabolism 1. The protein facilitates uptake of dietary retinoids, retinoid metabolism in enterocytes, and local retinoid actions within the intestine 1. Mechanistically, RBP2 exhibits unexpected versatility by binding long-chain 2-monoacylglycerols (2-MAGs), including the endocannabinoid 2-arachidonoylglycerol, with affinity equivalent to retinol binding 12. Crystallographic studies reveal that 2-MAGs bind to the same site as retinol, making RBP2 a nexus where retinoid and endocannabinoid signaling pathways converge 3. In disease contexts, RBP2 deficiency leads to metabolic dysfunction including obesity, glucose intolerance, and fatty liver when mice are maintained on high-fat diets 1. Additionally, RBP2 functions as a histone demethylase involved in cancer progression, promoting epithelial-mesenchymal transition and metastasis in gastric and ovarian cancers through regulation of E-cadherin expression 45. Clinical significance includes its identification as a potential biomarker for ARDS and therapeutic target, with elevated expression correlating with poor prognosis in ovarian cancer patients 65.