Organic anion transporters (OATs) are a group of membrane proteins that play a crucial role in the transport of various organic anions across cell membranes. These proteins are primarily expressed in the kidney, liver, and intestine, where they participate in the uptake and excretion of a wide range of endogenous and exogenous organic anions. The OAT protein family belongs to the larger solute carrier (SLC) superfamily, specifically the SLC22 family. OATs are transmembrane proteins composed of 12 alpha-helical transmembrane domains (TMDs) connected by intracellular and extracellular loops. They exhibit a topology where the N-terminus is located intracellularly, while the C-terminus faces the extracellular space. There are several isoforms of OATs, including OAT1 (SLC22A6), OAT2 (SLC22A7), OAT3 (SLC22A8), and OAT4 (SLC22A11), which have been extensively studied. Each isoform has a unique tissue distribution, substrate specificity, and physiological role.The primary function of OATs is to mediate the uptake of organic anions from the bloodstream into the cells, or their excretion from the cells into the blood or urine, depending on the tissue and physiological context. OATs are involved in the transport of a wide array of endogenous compounds, such as hormones, neurotransmitters, bile acids, uric acid, and various drugs and xenobiotics. OATs operate via facilitated diffusion, utilizing the electrochemical gradient established across the cell membrane. They utilize the transmembrane ion gradient of sodium (Na+) or protons (H+) to drive the transport of organic anions. This process is often coupled with the transport of Na+ or H+ ions, depending on the isoform. The binding of organic anions to the OAT protein triggers conformational changes, allowing the substrate to be translocated across the membrane. OAT expression can be modulated at the transcriptional level by factors such as nuclear receptors and cytokines. Post-translational modifications, including phosphorylation, can also influence OAT function. Overall, organic anion transporters (OATs) are essential proteins involved in the absorption, distribution, and elimination of organic anions in the body. Their role in anion transport makes them significant targets for scientific research. OAT1 inhibitors offered by Santa Cruz Biotechnology inhibit OAT1 and, in some cases, other membrane proteins.